* Re: [PATCH V2 1/8] PCI: imx6: Add skip_pwrctrl_off flag support
From: Manivannan Sadhasivam @ 2026-06-25 13:57 UTC (permalink / raw)
To: Sherry Sun
Cc: Frank Li (OSS), Sherry Sun (OSS), robh@kernel.org,
krzk+dt@kernel.org, conor+dt@kernel.org, Frank Li,
s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com,
Amitkumar Karwar, Neeraj Sanjay Kale, marcel@holtmann.org,
luiz.dentz@gmail.com, Hongxing Zhu, l.stach@pengutronix.de,
lpieralisi@kernel.org, kwilczynski@kernel.org,
bhelgaas@google.com, brgl@kernel.org, imx@lists.linux.dev,
linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-bluetooth@vger.kernel.org, linux-pm@vger.kernel.org
In-Reply-To: <VI0PR04MB12114BCBD405505888063284492EC2@VI0PR04MB12114.eurprd04.prod.outlook.com>
On Thu, Jun 25, 2026 at 07:25:46AM +0000, Sherry Sun wrote:
> > Subject: Re: [PATCH V2 1/8] PCI: imx6: Add skip_pwrctrl_off flag support
> >
> > On Wed, Jun 24, 2026 at 07:09:26AM +0000, Sherry Sun wrote:
> > > > Subject: Re: [PATCH V2 1/8] PCI: imx6: Add skip_pwrctrl_off flag
> > > > support
> > > >
> > > > On Tue, Jun 23, 2026 at 11:07:28AM +0800, Sherry Sun (OSS) wrote:
> > > > > From: Sherry Sun <sherry.sun@nxp.com>
> > > > >
> > > > > Use dw_pcie_rp::skip_pwrctrl_off to avoid powering off devices
> > > > > during suspend to preserve wakeup capability of the devices and
> > > > > also not to power on the devices in the init path.
> > > > > This allows controller power-off to be skipped when some devices(e.g.
> > > > > M.2 cards key E without auxiliary power) required to support PCIe
> > > > > L2 link state and wake-up mechanisms.
> > > > >
> > > > > Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
> > > > > ---
> > > > > drivers/pci/controller/dwc/pci-imx6.c | 36
> > > > > +++++++++++++++++----------
> > > > > 1 file changed, 23 insertions(+), 13 deletions(-)
> > > > >
> > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > > > index 0fa716d1ed75..ff5a9565dbbf 100644
> > > > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > > > @@ -1382,16 +1382,20 @@ static int imx_pcie_host_init(struct
> > > > > dw_pcie_rp
> > > > *pp)
> > > > > }
> > > > > }
> > > > >
> > > > > - ret = pci_pwrctrl_create_devices(dev);
> > > > > - if (ret) {
> > > > > - dev_err(dev, "failed to create pwrctrl devices\n");
> > > > > - goto err_reg_disable;
> > > > > + if (!pci->suspended) {
> > > > > + ret = pci_pwrctrl_create_devices(dev);
> > > >
> > > > Is possible move pci_pwrctrl_create_devices() of
> > > > pci_pwrctrl_create_devices
> > > >
> > > > and call it direct at probe() function, like other regulator_get function.
> > > >
> > >
> > > Hi Frank,
> > > That makes sense. However, if we move pci_pwrctrl_create_devices () to
> > > probe(), we may need to add the following goto err_pwrctrl_destroy
> > > path in imx_pcie_probe() to properly handle errors from
> > > pci_pwrctrl_power_on_devices(), is that acceptable?
> >
> > Can you add a API devm_pci_pwrctrl_create_devices() ?
> >
>
> Hi Frank, we cannot unconditionally destroy the pwrctrl devices
> when probing fails by using devm API.
> Since we need to check the return value of
> pci_pwrctrl_power_on_devices() for example EPROBE_DEFER to decide
> whether to destroy the pwrctrl devices to avoid the deferred probe loop.
>
> You can find more related discussion here.
> https://lore.kernel.org/all/tutxwjciedqoje5wxvtin4h637auni5zzpvb7rtfg4uticxoux@yfl6xg7oht7t/
>
Yes. Ideally we should try to do a blocking wait in the pwrctrl core until all
the pwrctrl drivers are probed, instead of deferring probe. Hopefully, I'll get
to it soon.
- Mani
--
மணிவண்ணன் சதாசிவம்
^ permalink raw reply
* Re: [PATCH v18 4/8] rust: page: convert to `Ownable`
From: Gary Guo @ 2026-06-25 13:32 UTC (permalink / raw)
To: Andreas Hindborg, Danilo Krummrich, Lorenzo Stoakes,
Vlastimil Babka, Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda,
Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Alice Ryhl, Trevor Gross, Daniel Almeida, Tamir Duberstein,
Alexandre Courbot, Onur Özkan, Lyude Paul,
Greg Kroah-Hartman, Arve Hjønnevåg, Todd Kjos,
Christian Brauner, Carlos Llamas, Rafael J. Wysocki, Dave Ertman,
Ira Weiny, Leon Romanovsky, Paul Moore, Serge Hallyn,
David Airlie, Simona Vetter, Alexander Viro, Jan Kara,
Igor Korotin, Viresh Kumar, Nishanth Menon, Stephen Boyd,
Bjorn Helgaas, Krzysztof Wilczyński, Pavel Tikhomirov,
Michal Wilczynski
Cc: Philipp Stanner, rust-for-linux, linux-kernel, linux-mm,
driver-core, linux-block, linux-security-module, dri-devel,
linux-fsdevel, linux-pm, linux-pci, linux-pwm, Asahi Lina
In-Reply-To: <20260625-unique-ref-v18-4-4e06b5896d47@kernel.org>
On Thu Jun 25, 2026 at 11:15 AM BST, Andreas Hindborg wrote:
> From: Asahi Lina <lina@asahilina.net>
>
> This allows Page references to be returned as borrowed references,
> without necessarily owning the struct page.
>
> Remove `BorrowedPage` and update users to use `Owned<Page>`.
>
> Signed-off-by: Asahi Lina <lina@asahilina.net>
> [ Andreas: Fix formatting and add a safety comment, update users. ]
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Nice to see `BorrowedPage` going away.
Reviewed-by: Gary Guo <gary@garyguo.net>
> ---
> drivers/android/binder/page_range.rs | 10 +--
> rust/kernel/alloc/allocator.rs | 19 +++---
> rust/kernel/alloc/allocator/iter.rs | 6 +-
> rust/kernel/page.rs | 122 +++++++++--------------------------
> 4 files changed, 46 insertions(+), 111 deletions(-)
^ permalink raw reply
* Re: [PATCH v18 3/8] rust: implement `ForeignOwnable` for `Owned`
From: Gary Guo @ 2026-06-25 13:29 UTC (permalink / raw)
To: Andreas Hindborg, Danilo Krummrich, Lorenzo Stoakes,
Vlastimil Babka, Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda,
Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Alice Ryhl, Trevor Gross, Daniel Almeida, Tamir Duberstein,
Alexandre Courbot, Onur Özkan, Lyude Paul,
Greg Kroah-Hartman, Arve Hjønnevåg, Todd Kjos,
Christian Brauner, Carlos Llamas, Rafael J. Wysocki, Dave Ertman,
Ira Weiny, Leon Romanovsky, Paul Moore, Serge Hallyn,
David Airlie, Simona Vetter, Alexander Viro, Jan Kara,
Igor Korotin, Viresh Kumar, Nishanth Menon, Stephen Boyd,
Bjorn Helgaas, Krzysztof Wilczyński, Pavel Tikhomirov,
Michal Wilczynski
Cc: Philipp Stanner, rust-for-linux, linux-kernel, linux-mm,
driver-core, linux-block, linux-security-module, dri-devel,
linux-fsdevel, linux-pm, linux-pci, linux-pwm
In-Reply-To: <20260625-unique-ref-v18-3-4e06b5896d47@kernel.org>
On Thu Jun 25, 2026 at 11:15 AM BST, Andreas Hindborg wrote:
> Implement `ForeignOwnable` for `Owned<T>`. This allows use of `Owned<T>` in
> places such as the `XArray`.
>
> Note that `T` does not need to implement `ForeignOwnable` for `Owned<T>` to
> implement `ForeignOwnable`.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> ---
> rust/kernel/owned.rs | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/rust/kernel/owned.rs b/rust/kernel/owned.rs
> index 7fe9ec3e55126..9c92d4a83cc1b 100644
> --- a/rust/kernel/owned.rs
> +++ b/rust/kernel/owned.rs
> @@ -15,6 +15,8 @@
> ptr::NonNull, //
> };
>
> +use kernel::types::ForeignOwnable;
> +
> /// Types that specify their own way of performing allocation and destruction. Typically, this trait
> /// is implemented on types from the C side.
> ///
> @@ -186,3 +188,54 @@ fn drop(&mut self) {
> unsafe { T::release(self.ptr) };
> }
> }
> +
> +// SAFETY: We derive the pointer to `T` from a valid `T`, so the returned
> +// pointer satisfy alignment requirements of `T`.
> +unsafe impl<T: Ownable> ForeignOwnable for Owned<T> {
> + const FOREIGN_ALIGN: usize = core::mem::align_of::<T>();
> +
> + type Borrowed<'a>
> + = &'a T
> + where
> + Self: 'a;
> + type BorrowedMut<'a>
> + = Pin<&'a mut T>
> + where
> + Self: 'a;
> +
> + #[inline]
> + fn into_foreign(self) -> *mut kernel::ffi::c_void {
> + let ptr = self.ptr.as_ptr().cast();
> + core::mem::forget(self);
> + ptr
I think the pattern in `into_raw` is better:
ManuallyDrop::new(self).ptr.as_ptr().cast()
Or perhaps this can just use `Self::into_raw(self).as_ptr().cast()`.
> + }
> +
> + #[inline]
> + unsafe fn from_foreign(ptr: *mut kernel::ffi::c_void) -> Self {
> + // INVARIANT: By the function safety contract, `ptr` was returned by `into_foreign`, which
> + // gave up exclusive ownership of a valid, pinned `T`; we retake that ownership here.
> + Self {
> + // SAFETY: By function safety contract, `ptr` came from
> + // `into_foreign` and cannot be null.
> + ptr: unsafe { NonNull::new_unchecked(ptr.cast()) },
> + }
> + }
Same here, could be using `Self::from_raw`.
However, the current code looks correct to me regardless, so:
Reviewed-by: Gary Guo <gary@garyguo.net>
Best,
Gary
> +
> + #[inline]
> + unsafe fn borrow<'a>(ptr: *mut kernel::ffi::c_void) -> Self::Borrowed<'a> {
> + // SAFETY: By function safety requirements, `ptr` is valid for use as a
> + // reference for `'a`.
> + unsafe { &*ptr.cast() }
> + }
> +
> + #[inline]
> + unsafe fn borrow_mut<'a>(ptr: *mut kernel::ffi::c_void) -> Self::BorrowedMut<'a> {
> + // SAFETY: By function safety requirements, `ptr` is valid for use as a
> + // unique reference for `'a`.
> + let inner = unsafe { &mut *ptr.cast() };
> +
> + // SAFETY: We never move out of inner, and we do not hand out mutable
> + // references when `T: !Unpin`.
> + unsafe { Pin::new_unchecked(inner) }
> + }
> +}
^ permalink raw reply
* [PATCH] selftests: helpers: handle multi line in test_sysfs_prop_optional_list
From: Boris Shtrasman @ 2026-06-25 12:52 UTC (permalink / raw)
To: Sebastian Reichel, Shuah Khan
Cc: linux-pm, linux-kselftest, linux-kernel, Boris Shtrasman
Modify test_sysfs_prop_optional_list to allow multi line parameters, in
order to comply with checkpatch output that limit line by 100 chars.
Allow use cases like:
test_sysfs_prop_optional_list \
property_name "value1","value2","val3","very_long_option"\
,"extra_long_option" \
,"even_more_data"
Signed-off-by: Boris Shtrasman <borissh1983@gmail.com>
---
tools/testing/selftests/power_supply/helpers.sh | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/power_supply/helpers.sh b/tools/testing/selftests/power_supply/helpers.sh
index 1ec90d7c9108..8535cb7ed094 100644
--- a/tools/testing/selftests/power_supply/helpers.sh
+++ b/tools/testing/selftests/power_supply/helpers.sh
@@ -108,7 +108,7 @@ test_sysfs_prop_optional_range() {
test_sysfs_prop_optional_list() {
PROP=$1
- LIST=$2
+ shift
TEST_NAME="$DEVNAME".sysfs."$PROP"
@@ -118,9 +118,9 @@ test_sysfs_prop_optional_list() {
valid=0
OLDIFS=$IFS
- IFS=","
- for item in $LIST; do
- if [ "$DATA" = "$item" ]; then
+ IFS=",IFS"
+ for item in $*; do
+ if [ "$item" ] && [ "$DATA" = "$item" ]; then
valid=1
break
fi
--
2.47.3
^ permalink raw reply related
* Re: [PATCH v2 1/2] dt-bindings: power: supply: Add TI BQ25630 charger
From: Waqar Hameed @ 2026-06-25 12:20 UTC (permalink / raw)
To: Krzysztof Kozlowski
Cc: Sebastian Reichel, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
kernel, linux-pm, devicetree, linux-kernel
In-Reply-To: <18ae59ae-024f-4dfb-ad66-2db90e6f7ed4@kernel.org>
On Thu, Jun 25, 2026 at 14:10 +0200 Krzysztof Kozlowski <krzk@kernel.org> wrote:
> On 25/06/2026 13:27, Waqar Hameed wrote:
>>>> +
>>>> +required:
>>>> + - compatible
>>>> + - reg
>>>> + - interrupts
>>>> + - monitored-battery
>>>> +
>>>> +additionalProperties: false
>>>
>>> And here use 'unevaluatedProperties: false' instead.
>>
>> Hm, reading the documentation [1], `unevaluatedProperties` should be
>> used, because of the "include" of `power-supply.yaml`. I'll change to
>> that.
>>
>> However, there are tons of other places where `additionalProperties` is
>> used instead _with_ a reference to `power-supply.yaml` (which is what I
>> followed). Are all of them actually "wrong" then?
>
> No, they are not wrong, but usually preferred is to allow all properties
> from referenced power-supply schema.
Ah ok, I can see why it's more preferable to be more "permissive" with
`unevaluatedProperties`. Thanks!
^ permalink raw reply
* Re: [PATCH v2 1/2] dt-bindings: power: supply: Add TI BQ25630 charger
From: Krzysztof Kozlowski @ 2026-06-25 12:10 UTC (permalink / raw)
To: Waqar Hameed
Cc: Sebastian Reichel, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
kernel, linux-pm, devicetree, linux-kernel
In-Reply-To: <pndwlvm6ese.a.out@axis.com>
On 25/06/2026 13:27, Waqar Hameed wrote:
>>> +
>>> +required:
>>> + - compatible
>>> + - reg
>>> + - interrupts
>>> + - monitored-battery
>>> +
>>> +additionalProperties: false
>>
>> And here use 'unevaluatedProperties: false' instead.
>
> Hm, reading the documentation [1], `unevaluatedProperties` should be
> used, because of the "include" of `power-supply.yaml`. I'll change to
> that.
>
> However, there are tons of other places where `additionalProperties` is
> used instead _with_ a reference to `power-supply.yaml` (which is what I
> followed). Are all of them actually "wrong" then?
No, they are not wrong, but usually preferred is to allow all properties
from referenced power-supply schema.
Best regards,
Krzysztof
^ permalink raw reply
* Re: [PATCH v11 6/7] power: reset: add PSCR NVMEM Driver for Recording Power State Change Reasons
From: Faruque Ansari @ 2026-06-25 11:52 UTC (permalink / raw)
To: Oleksij Rempel, Sebastian Reichel, Srinivas Kandagatla,
Benson Leung, Tzung-Bi Shih, Daniel Lezcano
Cc: kernel, linux-kernel, Liam Girdwood, Mark Brown,
Rafael J. Wysocki, Zhang Rui, Lukasz Luba, linux-pm,
Søren Andersen, Guenter Roeck, Matti Vaittinen, Ahmad Fatoum,
Andrew Morton, chrome-platform, umang.chheda
In-Reply-To: <20250618120255.3141862-7-o.rempel@pengutronix.de>
Hi Oleksij,
On 18-Jun-25 5:32 PM, Oleksij Rempel wrote:
> This driver utilizes the Power State Change Reasons Recording (PSCRR)
> framework to store specific power state change information, such as
> shutdown or reboot reasons, into a designated non-volatile memory
> (NVMEM) cell.
>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
> changes v6:
> - rename pscr_reason to psc_reason
> changes v5:
> - avoid a build against NVMEM=m
> changes v4:
> - remove devicetree dependencies
> ---
> drivers/power/reset/Kconfig | 22 +++
> drivers/power/reset/Makefile | 1 +
> drivers/power/reset/pscrr-nvmem.c | 254 ++++++++++++++++++++++++++++++
> 3 files changed, 277 insertions(+)
> create mode 100644 drivers/power/reset/pscrr-nvmem.c
Tested-by: Faruque Ansari <faruque.ansari@oss.qualcomm.com>
I have tested this on Qualcomm's lemans-evk and monaco-evk platforms.
The testing was performed across the following scenarios:
Userspace sys node to set reboot parameter
- Tested the userspace node interface used to configure the reboot
parameter confirmed that the parameter is applied correctly and
visible post reboot by reading back the sysfs node.
Overtemperature shutdown
- Simulated fake over-temperature condition and verified that
proper reason is being reflected in the sysfs node post reboot.
I did not observe any functional issues during testing on either of
platforms.
Thanks for this patch - it is helpful for us as well.
Best regards,
Faruque Ansari <faruque.ansari@oss.qualcomm.com>
^ permalink raw reply
* Re: [PATCH v2 1/2] dt-bindings: power: supply: Add TI BQ25630 charger
From: Waqar Hameed @ 2026-06-25 11:27 UTC (permalink / raw)
To: Krzysztof Kozlowski
Cc: Sebastian Reichel, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
kernel, linux-pm, devicetree, linux-kernel
In-Reply-To: <20260622-whimsical-inescapable-pronghorn-5f94bb@quoll>
On Mon, Jun 22, 2026 at 13:06 +0200 Krzysztof Kozlowski <krzk@kernel.org> wrote:
> On Thu, Jun 18, 2026 at 03:37:59PM +0200, Waqar Hameed wrote:
>> +allOf:
>> + - $ref: power-supply.yaml#
>> +
>> +properties:
>> + compatible:
>> + const: ti,bq25630
>> +
>> + reg:
>> + const: 0x6b
>> + description:
>> + Device I2C address.
>
> Drop description, obvious.
I see that several others actually don't have a description for this
property. I'll drop it!
>
>> +
>> + interrupts:
>> + maxItems: 1
>> + description: |
>
> Do not need '|' unless you need to preserve formatting.
Right, let's remove it.
>
>> + Device sends active low 256 µs pulse. Type should therefore be
>> + IRQ_TYPE_EDGE_FALLING.
>> +
>> + monitored-battery: true
>
> Drop this one
I was actually unsure about this one, but several other bindings had
this one. We can remove it.
>
>> +
>> +required:
>> + - compatible
>> + - reg
>> + - interrupts
>> + - monitored-battery
>> +
>> +additionalProperties: false
>
> And here use 'unevaluatedProperties: false' instead.
Hm, reading the documentation [1], `unevaluatedProperties` should be
used, because of the "include" of `power-supply.yaml`. I'll change to
that.
However, there are tons of other places where `additionalProperties` is
used instead _with_ a reference to `power-supply.yaml` (which is what I
followed). Are all of them actually "wrong" then?
>
> With these fixed:
>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Thank you for your review Krzysztof!
[1] `Documentation/devicetree/bindings/writing-schema.rst`
^ permalink raw reply
* Re: [PATCH v3 1/7] list: Add mutable iterator variants
From: Jani Nikula @ 2026-06-25 11:00 UTC (permalink / raw)
To: Kaitao Cheng, David Laight, Christian König,
David Hildenbrand (Arm), Alexei Starovoitov
Cc: Andrew Morton, David Hildenbrand, Jens Axboe, Tejun Heo,
Alexander Viro, Christian Brauner, Daniel Borkmann,
Andrii Nakryiko, Johannes Weiner, Peter Zijlstra, Ingo Molnar,
Arnaldo Carvalho de Melo, Namhyung Kim, Thomas Gleixner,
Juri Lelli, Vincent Guittot, Paul Moore, Andy Shevchenko,
Paul E. McKenney, Shakeel Butt, David Howells, Simona Vetter,
Randy Dunlap, Luca Ceresoli, Philipp Stanner, linux-block,
linux-kernel, cgroups, linux-ntfs-dev, linux-fsdevel, io-uring,
audit, bpf, netdev, dri-devel, linux-perf-users,
linux-trace-kernel, kexec, live-patching, linux-modules,
linux-crypto, linux-pm, rcu, sched-ext, linux-mm, virtualization,
damon, llvm, Kaitao Cheng, Muchun Song
In-Reply-To: <0ed6b5c3-e955-46e2-9fc6-075a0dfd1c4f@linux.dev>
On Thu, 25 Jun 2026, Kaitao Cheng <kaitao.cheng@linux.dev> wrote:
> 在 2026/6/24 22:23, David Laight 写道:
>> On Wed, 24 Jun 2026 15:23:47 +0200
>> Christian König <christian.koenig@amd.com> wrote:
>>> On 6/24/26 15:14, Kaitao Cheng wrote:
>>>> 在 2026/6/22 16:42, David Laight 写道:
>>>>> On Mon, 22 Jun 2026 12:05:31 +0800
>>>>> Kaitao Cheng <kaitao.cheng@linux.dev> wrote:
>>>>>
>>>>>> From: Kaitao Cheng <chengkaitao@kylinos.cn>
>>>>>>
>>>>>> The list_for_each*_safe() helpers are used when the loop body may
>>>>>> remove the current entry. Their API exposes the temporary cursor at
>>>>>> every call site, even though most users only need it for the iterator
>>>>>> implementation and never reference it in the loop body.
>>>>>>
>>>>>> Add *_mutable() variants for list and hlist iteration. The new helpers
>>>>>> support both forms: callers may keep passing an explicit temporary cursor
>>>>>> when they need to inspect or reset it, or omit it and let the helper use
>>>>>> a unique internal cursor.
>>>>>
>>>>> I'm not really sure 'mutable' means anything either.
>>>>> It is possible to make it valid for the loop body (or even other threads)
>>>>> to delete arbitrary list items - but that needs significant extra overheads.
>>>>>
>>>>> It might be worth doing something that doesn't need the extra variable,
>>>>> but there is little point doing all the churn just to rename things.
>>>>>
>>>>>>
>>>>>> This makes call sites that only mutate the list through the current entry
>>>>>> less noisy, while keeping the existing *_safe() helpers available for
>>>>>> compatibility.
>>>>>>
>>>>>> Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
>>>>>> ---
>>>>>> include/linux/list.h | 269 +++++++++++++++++++++++++++++++++++++------
>>>>>> 1 file changed, 231 insertions(+), 38 deletions(-)
>>>>>>
>>>>>> diff --git a/include/linux/list.h b/include/linux/list.h
>>>>>> index 09d979976b3b..1081def7cea9 100644
>>>>>> --- a/include/linux/list.h
>>>>>> +++ b/include/linux/list.h
>>>>>> @@ -7,6 +7,7 @@
>>>>>> #include <linux/stddef.h>
>>>>>> #include <linux/poison.h>
>>>>>> #include <linux/const.h>
>>>>>> +#include <linux/args.h>
>>>>>>
>>>>>> #include <asm/barrier.h>
>>>>>>
>>>>>> @@ -763,28 +764,72 @@ static inline void list_splice_tail_init(struct list_head *list,
>>>>>> #define list_for_each_prev(pos, head) \
>>>>>> for (pos = (head)->prev; !list_is_head(pos, (head)); pos = pos->prev)
>>>>>>
>>>>>> -/**
>>>>>> - * list_for_each_safe - iterate over a list safe against removal of list entry
>>>>>> - * @pos: the &struct list_head to use as a loop cursor.
>>>>>> - * @n: another &struct list_head to use as temporary storage
>>>>>> - * @head: the head for your list.
>>>>>> +/*
>>>>>> + * list_for_each_safe is an old interface, use list_for_each_mutable instead.
>>>>>> */
>>>>>> #define list_for_each_safe(pos, n, head) \
>>>>>> for (pos = (head)->next, n = pos->next; \
>>>>>> !list_is_head(pos, (head)); \
>>>>>> pos = n, n = pos->next)
>>>>>>
>>>>>> +#define __list_for_each_mutable_internal(pos, tmp, head) \
>>>>>> + for (typeof(pos) tmp = (pos = (head)->next)->next; \
>>>>>
>>>>> Use auto
>>>>>
>>>>>> + !list_is_head(pos, (head)); \
>>>>>> + pos = tmp, tmp = pos->next)
>>>>>> +
>>>>>> +#define __list_for_each_mutable1(pos, head) \
>>>>>> + __list_for_each_mutable_internal(pos, __UNIQUE_ID(next), head)
>>>>>> +
>>>>>> +#define __list_for_each_mutable2(pos, next, head) \
>>>>>> + list_for_each_safe(pos, next, head)
>>>>>> +
>>>>>> /**
>>>>>> - * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
>>>>>> + * list_for_each_mutable - iterate over a list safe against entry removal
>>>>>> * @pos: the &struct list_head to use as a loop cursor.
>>>>>> - * @n: another &struct list_head to use as temporary storage
>>>>>> - * @head: the head for your list.
>>>>>> + * @...: either (head) or (next, head)
>>>>>> + *
>>>>>> + * next: another &struct list_head to use as optional temporary storage.
>>>>>> + * The temporary cursor is internal unless explicitly supplied by
>>>>>> + * the caller.
>>>>>> + * head: the head for your list.
>>>>>> + */
>>>>>> +#define list_for_each_mutable(pos, ...) \
>>>>>> + CONCATENATE(__list_for_each_mutable, COUNT_ARGS(__VA_ARGS__)) \
>>>>>> + (pos, __VA_ARGS__)
>>>>>
>>>>> The variable argument count logic really just slows down compilation.
>>>>> Maybe there aren't enough copies of this code to make that significant.
>>>>> But just because you can do it doesn't mean it is a gooD idea.
>>>>> I'm also not sure it really adds anything to the readability.
>>>>>
>>>>> And, it you are going to make the middle argument optional there is
>>>>> no need to change the macro name.
>>>>
>>>> Christian König and Jani Nikula also disagree with the variadic-argument
>>>> implementation approach. If we abandon that method, it means we will
>>>> inevitably need to add some new macros. If mutable is not a good name,
>>>> suggestions for better alternatives would be welcome; coming up with a
>>>> suitable name is indeed rather tricky.
>>>
>>> I don't think you need to add a new macro for the specific use case that people want to modify the next element of the iteration.
>>>
>>> If I remember your numbers correctly that is a really corner case and keeping using the existing *_safe() macros for that sounds perfectly fine to me.
>>
>> IIRC currently you have a choice of either:
>> define Item that can't be deleted
>> list_for_each() The current item.
>> list_for_each_safe() The next item.
>> There is also likely to be code that updates the variables to allow
>> for other scenarios.
>>
>> Note that if increase a reference count and release a lock then list_for_each()
>> is likely safer than list_for_each_safe() :-)
>>
>> list.h has 9 variants of the 'safe' loop.
>> The bloat of another 9 is getting excessive.
>>
>> It has to be said that this is one of my least favourite type of list...
>
> Hi Christian König, David Laight, Jani Nikula, David Hildenbrand,
> Andy Shevchenko, Alexei Starovoitov
>
> For ease of discussion, I need to summarize the currently possible
> approaches and briefly describe their respective pros and cons,
> using the list_for_each_entry* interfaces as examples.
>
> 1. Add list_for_each_entry_mutable, while keeping list_for_each_entry
> and list_for_each_entry_safe unchanged. list_for_each_entry_mutable
> would be used specifically for safe deletion scenarios that do not
> need to expose the temporary cursor externally. The code can refer to
> the v1 version.
>
> Pros: Does not depend on immediate per-subsystem adaptation and can be
> merged directly.
> Cons: Requires adding a whole set of mutable interfaces, which makes the
> code somewhat redundant.
Seems fine, and the original _safe naming is ambiguous anyway.
> 2. Directly optimize away the temporary cursor in list_for_each_entry_safe
> and define it inside the loop instead, changing the interface from four
> arguments to three.
>
> Pros: Does not add redundant interfaces.
> Cons: (1) Users need to manually update special cases that use the
> traversal variable of list_for_each_entry_safe, the new
> list_for_each_entry_safe would no longer apply there and would
> need to be open-coded.
> (2) Because the macro arguments changes, all list_for_each_entry_safe
> callers would need to be modified and merged together, making it
> difficult to merge such a large amount of code at once.
This won't fly because there are literally thousands of
list_for_each_entry_safe() users.
> 3. Use a variadic macro approach to optimize list_for_each_entry_safe,
> so that it supports both three and four arguments.
>
> Pros: (1) Does not add redundant interfaces.
> (2) Does not depend on immediate per-subsystem adaptation and can
> be merged directly.
> Cons: (1) Increases compile time.
> (2) Makes the interface harder for users to use.
Basically I'm against any variadic macro tricks where the optional
argument is not the last argument. That's just way too surprising, and
goes against common practice in just about all other languages.
> 4. Optimize list_for_each_entry by defining the temporary cursor internally,
> making it compatible with the functionality of list_for_each_entry_safe.
> The code can refer to the v2 version.
>
> Pros: (1) Does not add redundant interfaces.
> (2) The number of externally visible arguments of list_for_each_entry
> remains unchanged, still three.
> Cons: (1) list_for_each_entry and list_for_each_entry_safe would be merged
> into one, and list_for_each_entry_safe would gradually be deprecated.
> (2) Users need to manually update special cases that use the traversal
> variable of list_for_each_entry, the new list_for_each_entry would no
> longer apply there and would need to be open-coded. There are 15 such
> cases in total.
This sounds good to me, though I take it there's some code size increase
and/or performance penalty?
Maybe the 15 cases are questionable anyway?
> 5. Use a variadic macro approach to optimize list_for_each_entry, so that
> it supports both three and four arguments.
>
> Pros: (1) Does not add redundant interfaces.
> (2) Does not depend on immediate per-subsystem adaptation and can be
> merged directly.
> Cons: (1) Increases compile time.
> (2) list_for_each_entry and list_for_each_entry_safe would be merged
> into one, and list_for_each_entry_safe would gradually be deprecated.
Please don't do the macro tricks.
> 6. Make no changes, keep the current logic unchanged, and close the current
> email discussion.
I like hiding the temporary stuff when possible.
BR,
Jani.
--
Jani Nikula, Intel
^ permalink raw reply
* [PATCH v18 5/8] rust: rename `AlwaysRefCounted` to `RefCounted`.
From: Andreas Hindborg @ 2026-06-25 10:15 UTC (permalink / raw)
To: Danilo Krummrich, Lorenzo Stoakes, Vlastimil Babka,
Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda, Boqun Feng,
Gary Guo, Björn Roy Baron, Benno Lossin, Alice Ryhl,
Trevor Gross, Daniel Almeida, Tamir Duberstein, Alexandre Courbot,
Onur Özkan, Lyude Paul, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Rafael J. Wysocki, Dave Ertman, Ira Weiny,
Leon Romanovsky, Paul Moore, Serge Hallyn, David Airlie,
Simona Vetter, Alexander Viro, Jan Kara, Igor Korotin,
Viresh Kumar, Nishanth Menon, Stephen Boyd, Bjorn Helgaas,
Krzysztof Wilczyński, Pavel Tikhomirov, Michal Wilczynski
Cc: Andreas Hindborg, Philipp Stanner, rust-for-linux, linux-kernel,
linux-mm, driver-core, linux-block, linux-security-module,
dri-devel, linux-fsdevel, linux-pm, linux-pci, linux-pwm,
Oliver Mangold, Viresh Kumar, Igor Korotin
In-Reply-To: <20260625-unique-ref-v18-0-4e06b5896d47@kernel.org>
From: Oliver Mangold <oliver.mangold@pm.me>
There are types where it may both be reference counted in some cases and
owned in others. In such cases, obtaining `ARef<T>` from `&T` would be
unsound as it allows creation of `ARef<T>` copy from `&Owned<T>`.
Therefore, we split `AlwaysRefCounted` into `RefCounted` (which `ARef<T>`
would require) and a marker trait to indicate that the type is always
reference counted (and not `Ownable`) so the `&T` -> `ARef<T>` conversion
is possible.
- Rename `AlwaysRefCounted` to `RefCounted`.
- Add a new unsafe trait `AlwaysRefCounted`.
- Implement the new trait `AlwaysRefCounted` for the newly renamed
`RefCounted` implementations. This leaves functionality of existing
implementers of `AlwaysRefCounted` intact.
Suggested-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Oliver Mangold <oliver.mangold@pm.me>
[ Andreas: Updated commit message and rebase on rust-next (7.2) ]
Acked-by: Igor Korotin <igor.korotin.linux@gmail.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/auxiliary.rs | 10 +++++++-
rust/kernel/block/mq/request.rs | 19 +++++++++-----
rust/kernel/cred.rs | 16 ++++++++++--
rust/kernel/device.rs | 12 +++++++--
rust/kernel/device/property.rs | 11 ++++++--
rust/kernel/drm/device.rs | 9 +++++--
rust/kernel/drm/gem/mod.rs | 16 +++++++++---
rust/kernel/fs/file.rs | 23 ++++++++++++++---
rust/kernel/i2c.rs | 13 +++++++---
rust/kernel/mm.rs | 22 +++++++++++++---
rust/kernel/mm/mmput_async.rs | 12 +++++++--
rust/kernel/opp.rs | 16 +++++++++---
rust/kernel/owned.rs | 2 +-
rust/kernel/pci.rs | 10 +++++++-
rust/kernel/pid_namespace.rs | 15 +++++++++--
rust/kernel/platform.rs | 10 +++++++-
rust/kernel/pwm.rs | 12 +++++++--
rust/kernel/sync/aref.rs | 57 +++++++++++++++++++++++++----------------
rust/kernel/task.rs | 13 ++++++++--
rust/kernel/types.rs | 12 ++++++---
rust/kernel/usb.rs | 17 +++++++++---
21 files changed, 255 insertions(+), 72 deletions(-)
diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
index c42928d5a2393..854525289c8b4 100644
--- a/rust/kernel/auxiliary.rs
+++ b/rust/kernel/auxiliary.rs
@@ -19,6 +19,10 @@
to_result, //
},
prelude::*,
+ sync::aref::{
+ AlwaysRefCounted,
+ RefCounted, //
+ },
types::{
ForLt,
ForeignOwnable,
@@ -344,7 +348,7 @@ unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for Device<Ctx>
kernel::impl_device_context_into_aref!(Device);
// SAFETY: Instances of `Device` are always reference-counted.
-unsafe impl crate::sync::aref::AlwaysRefCounted for Device {
+unsafe impl RefCounted for Device {
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
unsafe { bindings::get_device(self.as_ref().as_raw()) };
@@ -363,6 +367,10 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Device>` from a
+// `&Device`.
+unsafe impl AlwaysRefCounted for Device {}
+
impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
fn as_ref(&self) -> &device::Device<Ctx> {
// SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index ce3e30c81cb5e..8dad15ae4cfb0 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -9,7 +9,11 @@
block::mq::Operations,
error::Result,
sync::{
- aref::{ARef, AlwaysRefCounted},
+ aref::{
+ ARef,
+ AlwaysRefCounted,
+ RefCounted, //
+ },
atomic::Relaxed,
Refcount,
},
@@ -229,11 +233,10 @@ unsafe impl<T: Operations> Send for Request<T> {}
// mutate `self` are internally synchronized`
unsafe impl<T: Operations> Sync for Request<T> {}
-// SAFETY: All instances of `Request<T>` are reference counted. This
-// implementation of `AlwaysRefCounted` ensure that increments to the ref count
-// keeps the object alive in memory at least until a matching reference count
-// decrement is executed.
-unsafe impl<T: Operations> AlwaysRefCounted for Request<T> {
+// SAFETY: All instances of `Request<T>` are reference counted. This implementation of `RefCounted`
+// ensure that increments to the ref count keeps the object alive in memory at least until a
+// matching reference count decrement is executed.
+unsafe impl<T: Operations> RefCounted for Request<T> {
fn inc_ref(&self) {
self.wrapper_ref().refcount().inc();
}
@@ -255,3 +258,7 @@ unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
}
}
}
+
+// SAFETY: We currently do not implement `Ownable`, thus it is okay to obtain an `ARef<Request>`
+// from a `&Request` (but this will change in the future).
+unsafe impl<T: Operations> AlwaysRefCounted for Request<T> {}
diff --git a/rust/kernel/cred.rs b/rust/kernel/cred.rs
index ffa156b9df377..b17736a9adcd5 100644
--- a/rust/kernel/cred.rs
+++ b/rust/kernel/cred.rs
@@ -8,7 +8,15 @@
//!
//! Reference: <https://www.kernel.org/doc/html/latest/security/credentials.html>
-use crate::{bindings, sync::aref::AlwaysRefCounted, task::Kuid, types::Opaque};
+use crate::{
+ bindings,
+ sync::aref::RefCounted,
+ task::Kuid,
+ types::{
+ AlwaysRefCounted,
+ Opaque, //
+ }, //
+};
/// Wraps the kernel's `struct cred`.
///
@@ -76,7 +84,7 @@ pub fn euid(&self) -> Kuid {
}
// SAFETY: The type invariants guarantee that `Credential` is always ref-counted.
-unsafe impl AlwaysRefCounted for Credential {
+unsafe impl RefCounted for Credential {
#[inline]
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference means that the refcount is nonzero.
@@ -90,3 +98,7 @@ unsafe fn dec_ref(obj: core::ptr::NonNull<Credential>) {
unsafe { bindings::put_cred(obj.cast().as_ptr()) };
}
}
+
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Credential>` from a
+// `&Credential`.
+unsafe impl AlwaysRefCounted for Credential {}
diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index 645afc49a27d6..2e90f6a06fd05 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -8,8 +8,12 @@
bindings,
fmt,
prelude::*,
- sync::aref::ARef,
+ sync::aref::{
+ ARef,
+ RefCounted, //
+ },
types::{
+ AlwaysRefCounted,
ForeignOwnable,
Opaque, //
}, //
@@ -448,7 +452,7 @@ pub fn name(&self) -> &CStr {
kernel::impl_device_context_into_aref!(Device);
// SAFETY: Instances of `Device` are always reference-counted.
-unsafe impl crate::sync::aref::AlwaysRefCounted for Device {
+unsafe impl RefCounted for Device {
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
unsafe { bindings::get_device(self.as_raw()) };
@@ -460,6 +464,10 @@ unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Device>` from a
+// `&Device`.
+unsafe impl AlwaysRefCounted for Device {}
+
// SAFETY: As by the type invariant `Device` can be sent to any thread.
unsafe impl Send for Device {}
diff --git a/rust/kernel/device/property.rs b/rust/kernel/device/property.rs
index 5aead835fbbc0..cee7e25013689 100644
--- a/rust/kernel/device/property.rs
+++ b/rust/kernel/device/property.rs
@@ -14,7 +14,10 @@
fmt,
prelude::*,
str::{CStr, CString},
- sync::aref::ARef,
+ sync::aref::{
+ ARef,
+ AlwaysRefCounted, //
+ },
types::Opaque,
};
@@ -360,7 +363,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
}
// SAFETY: Instances of `FwNode` are always reference-counted.
-unsafe impl crate::sync::aref::AlwaysRefCounted for FwNode {
+unsafe impl crate::sync::aref::RefCounted for FwNode {
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference guarantees that the
// refcount is non-zero.
@@ -374,6 +377,10 @@ unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<FwNode>` from a
+// `&FwNode`.
+unsafe impl AlwaysRefCounted for FwNode {}
+
enum Node<'a> {
Borrowed(&'a FwNode),
Owned(ARef<FwNode>),
diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs
index 403fc35353c74..368742a258376 100644
--- a/rust/kernel/drm/device.rs
+++ b/rust/kernel/drm/device.rs
@@ -15,7 +15,8 @@
prelude::*,
sync::aref::{
ARef,
- AlwaysRefCounted, //
+ AlwaysRefCounted,
+ RefCounted, //
},
types::Opaque,
workqueue::{
@@ -227,7 +228,7 @@ fn deref(&self) -> &Self::Target {
// SAFETY: DRM device objects are always reference counted and the get/put functions
// satisfy the requirements.
-unsafe impl<T: drm::Driver> AlwaysRefCounted for Device<T> {
+unsafe impl<T: drm::Driver> RefCounted for Device<T> {
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
unsafe { bindings::drm_dev_get(self.as_raw()) };
@@ -242,6 +243,10 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Device>` from a
+// `&Device`.
+unsafe impl<T: drm::Driver> AlwaysRefCounted for Device<T> {}
+
impl<T: drm::Driver> AsRef<device::Device> for Device<T> {
fn as_ref(&self) -> &device::Device {
// SAFETY: `bindings::drm_device::dev` is valid as long as the DRM device itself is valid,
diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs
index 01b5bd47a3332..30d3718578fe8 100644
--- a/rust/kernel/drm/gem/mod.rs
+++ b/rust/kernel/drm/gem/mod.rs
@@ -17,7 +17,7 @@
prelude::*,
sync::aref::{
ARef,
- AlwaysRefCounted, //
+ RefCounted, //
},
types::Opaque,
};
@@ -29,7 +29,7 @@
#[cfg(CONFIG_RUST_DRM_GEM_SHMEM_HELPER)]
pub mod shmem;
-/// A macro for implementing [`AlwaysRefCounted`] for any GEM object type.
+/// A macro for implementing [`RefCounted`] for any GEM object type.
///
/// Since all GEM objects use the same refcounting scheme.
#[macro_export]
@@ -42,7 +42,7 @@ impl $( <$( $tparam_id:ident ),+> )? for $type:ty
)?
) => {
// SAFETY: All GEM objects are refcounted.
- unsafe impl $( <$( $tparam_id ),+> )? $crate::sync::aref::AlwaysRefCounted for $type
+ unsafe impl $( <$( $tparam_id ),+> )? $crate::sync::aref::RefCounted for $type
where
Self: IntoGEMObject,
$( $( $bind_param : $bind_trait ),+ )?
@@ -61,6 +61,14 @@ unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
unsafe { bindings::drm_gem_object_put(obj) };
}
}
+
+ // SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<$type>` from a
+ // `&$type`.
+ unsafe impl $( <$( $tparam_id ),+> )? $crate::sync::aref::AlwaysRefCounted for $type
+ where
+ Self: IntoGEMObject,
+ $( $( $bind_param : $bind_trait ),+ )?
+ {}
};
}
#[cfg_attr(not(CONFIG_RUST_DRM_GEM_SHMEM_HELPER), allow(unused))]
@@ -98,7 +106,7 @@ fn close(_obj: &<Self::Driver as drm::Driver>::Object, _file: &DriverFile<Self>)
}
/// Trait that represents a GEM object subtype
-pub trait IntoGEMObject: Sized + super::private::Sealed + AlwaysRefCounted {
+pub trait IntoGEMObject: Sized + super::private::Sealed + RefCounted {
/// Returns a reference to the raw `drm_gem_object` structure, which must be valid as long as
/// this owning object is valid.
fn as_raw(&self) -> *mut bindings::drm_gem_object;
diff --git a/rust/kernel/fs/file.rs b/rust/kernel/fs/file.rs
index 23ee689bd2400..720e57418358d 100644
--- a/rust/kernel/fs/file.rs
+++ b/rust/kernel/fs/file.rs
@@ -12,8 +12,15 @@
cred::Credential,
error::{code::*, to_result, Error, Result},
fmt,
- sync::aref::{ARef, AlwaysRefCounted},
- types::{NotThreadSafe, Opaque},
+ sync::aref::{
+ ARef,
+ RefCounted, //
+ },
+ types::{
+ AlwaysRefCounted,
+ NotThreadSafe,
+ Opaque, //
+ }, //
};
use core::ptr;
@@ -197,7 +204,7 @@ unsafe impl Sync for File {}
// SAFETY: The type invariants guarantee that `File` is always ref-counted. This implementation
// makes `ARef<File>` own a normal refcount.
-unsafe impl AlwaysRefCounted for File {
+unsafe impl RefCounted for File {
#[inline]
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference means that the refcount is nonzero.
@@ -212,6 +219,10 @@ unsafe fn dec_ref(obj: ptr::NonNull<File>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<File>` from a
+// `&File`.
+unsafe impl AlwaysRefCounted for File {}
+
/// Wraps the kernel's `struct file`. Not thread safe.
///
/// This type represents a file that is not known to be safe to transfer across thread boundaries.
@@ -233,7 +244,7 @@ pub struct LocalFile {
// SAFETY: The type invariants guarantee that `LocalFile` is always ref-counted. This implementation
// makes `ARef<LocalFile>` own a normal refcount.
-unsafe impl AlwaysRefCounted for LocalFile {
+unsafe impl RefCounted for LocalFile {
#[inline]
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference means that the refcount is nonzero.
@@ -249,6 +260,10 @@ unsafe fn dec_ref(obj: ptr::NonNull<LocalFile>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<LocalFile>` from a
+// `&LocalFile`.
+unsafe impl AlwaysRefCounted for LocalFile {}
+
impl LocalFile {
/// Constructs a new `struct file` wrapper from a file descriptor.
///
diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
index 624b971ca8b0b..02b2c9220eb11 100644
--- a/rust/kernel/i2c.rs
+++ b/rust/kernel/i2c.rs
@@ -18,7 +18,8 @@
prelude::*,
sync::aref::{
ARef,
- AlwaysRefCounted, //
+ AlwaysRefCounted,
+ RefCounted, //
},
types::Opaque, //
};
@@ -424,7 +425,7 @@ pub fn get(index: i32) -> Result<ARef<Self>> {
kernel::impl_device_context_into_aref!(I2cAdapter);
// SAFETY: Instances of `I2cAdapter` are always reference-counted.
-unsafe impl AlwaysRefCounted for I2cAdapter {
+unsafe impl RefCounted for I2cAdapter {
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
unsafe { bindings::i2c_get_adapter(self.index()) };
@@ -435,6 +436,9 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
unsafe { bindings::i2c_put_adapter(obj.as_ref().as_raw()) }
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Device>` from an
+// `&I2cAdapter`.
+unsafe impl AlwaysRefCounted for I2cAdapter {}
/// The i2c board info representation
///
@@ -500,7 +504,7 @@ unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for I2cClient<C
kernel::impl_device_context_into_aref!(I2cClient);
// SAFETY: Instances of `I2cClient` are always reference-counted.
-unsafe impl AlwaysRefCounted for I2cClient {
+unsafe impl RefCounted for I2cClient {
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
unsafe { bindings::get_device(self.as_ref().as_raw()) };
@@ -511,6 +515,9 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
unsafe { bindings::put_device(&raw mut (*obj.as_ref().as_raw()).dev) }
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Device>` from an
+// `&I2cClient`.
+unsafe impl AlwaysRefCounted for I2cClient {}
impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for I2cClient<Ctx> {
fn as_ref(&self) -> &device::Device<Ctx> {
diff --git a/rust/kernel/mm.rs b/rust/kernel/mm.rs
index 4764d7b68f2a7..83ed94fca14ca 100644
--- a/rust/kernel/mm.rs
+++ b/rust/kernel/mm.rs
@@ -13,8 +13,15 @@
use crate::{
bindings,
- sync::aref::{ARef, AlwaysRefCounted},
- types::{NotThreadSafe, Opaque},
+ sync::aref::{
+ ARef,
+ RefCounted, //
+ },
+ types::{
+ AlwaysRefCounted,
+ NotThreadSafe,
+ Opaque, //
+ }, //
};
use core::{ops::Deref, ptr::NonNull};
@@ -55,7 +62,7 @@ unsafe impl Send for Mm {}
unsafe impl Sync for Mm {}
// SAFETY: By the type invariants, this type is always refcounted.
-unsafe impl AlwaysRefCounted for Mm {
+unsafe impl RefCounted for Mm {
#[inline]
fn inc_ref(&self) {
// SAFETY: The pointer is valid since self is a reference.
@@ -69,6 +76,9 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Mm>` from a `&Mm`.
+unsafe impl AlwaysRefCounted for Mm {}
+
/// A wrapper for the kernel's `struct mm_struct`.
///
/// This type is like [`Mm`], but with non-zero `mm_users`. It can only be used when `mm_users` can
@@ -91,7 +101,7 @@ unsafe impl Send for MmWithUser {}
unsafe impl Sync for MmWithUser {}
// SAFETY: By the type invariants, this type is always refcounted.
-unsafe impl AlwaysRefCounted for MmWithUser {
+unsafe impl RefCounted for MmWithUser {
#[inline]
fn inc_ref(&self) {
// SAFETY: The pointer is valid since self is a reference.
@@ -105,6 +115,10 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<MmWithUser>` from a
+// `&MmWithUser`.
+unsafe impl AlwaysRefCounted for MmWithUser {}
+
// Make all `Mm` methods available on `MmWithUser`.
impl Deref for MmWithUser {
type Target = Mm;
diff --git a/rust/kernel/mm/mmput_async.rs b/rust/kernel/mm/mmput_async.rs
index b8d2f051225c7..8fbc396e46028 100644
--- a/rust/kernel/mm/mmput_async.rs
+++ b/rust/kernel/mm/mmput_async.rs
@@ -10,7 +10,11 @@
use crate::{
bindings,
mm::MmWithUser,
- sync::aref::{ARef, AlwaysRefCounted},
+ sync::aref::{
+ ARef,
+ RefCounted, //
+ },
+ types::AlwaysRefCounted,
};
use core::{ops::Deref, ptr::NonNull};
@@ -34,7 +38,7 @@ unsafe impl Send for MmWithUserAsync {}
unsafe impl Sync for MmWithUserAsync {}
// SAFETY: By the type invariants, this type is always refcounted.
-unsafe impl AlwaysRefCounted for MmWithUserAsync {
+unsafe impl RefCounted for MmWithUserAsync {
#[inline]
fn inc_ref(&self) {
// SAFETY: The pointer is valid since self is a reference.
@@ -48,6 +52,10 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<MmWithUserAsync>`
+// from a `&MmWithUserAsync`.
+unsafe impl AlwaysRefCounted for MmWithUserAsync {}
+
// Make all `MmWithUser` methods available on `MmWithUserAsync`.
impl Deref for MmWithUserAsync {
type Target = MmWithUser;
diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs
index 62e44676125d1..b8db6bdefd077 100644
--- a/rust/kernel/opp.rs
+++ b/rust/kernel/opp.rs
@@ -16,8 +16,14 @@
ffi::{c_char, c_ulong},
prelude::*,
str::CString,
- sync::aref::{ARef, AlwaysRefCounted},
- types::Opaque,
+ sync::aref::{
+ ARef,
+ RefCounted, //
+ },
+ types::{
+ AlwaysRefCounted,
+ Opaque, //
+ }, //
};
#[cfg(CONFIG_CPU_FREQ)]
@@ -1041,7 +1047,7 @@ unsafe impl Send for OPP {}
unsafe impl Sync for OPP {}
/// SAFETY: The type invariants guarantee that [`OPP`] is always refcounted.
-unsafe impl AlwaysRefCounted for OPP {
+unsafe impl RefCounted for OPP {
#[inline]
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference means that the refcount is nonzero.
@@ -1055,6 +1061,10 @@ unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<OPP>` from an
+// `&OPP`.
+unsafe impl AlwaysRefCounted for OPP {}
+
impl OPP {
/// Creates an owned reference to a [`OPP`] from a valid pointer.
///
diff --git a/rust/kernel/owned.rs b/rust/kernel/owned.rs
index 9c92d4a83cc1b..e79936c00002c 100644
--- a/rust/kernel/owned.rs
+++ b/rust/kernel/owned.rs
@@ -27,7 +27,7 @@
///
/// Note: The underlying object is not required to provide internal reference counting, because it
/// represents a unique, owned reference. If reference counting (on the Rust side) is required,
-/// [`AlwaysRefCounted`](crate::sync::aref::AlwaysRefCounted) should be implemented.
+/// [`RefCounted`](crate::types::RefCounted) should be implemented.
///
/// # Examples
///
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 5071cae6543fd..ea9ef99cecb07 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -19,6 +19,10 @@
},
prelude::*,
str::CStr,
+ sync::aref::{
+ AlwaysRefCounted,
+ RefCounted, //
+ },
types::Opaque,
ThisModule, //
};
@@ -481,7 +485,7 @@ unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for Device<Ctx>
impl<'a> crate::dma::Device<'a> for Device<device::Core<'a>> {}
// SAFETY: Instances of `Device` are always reference-counted.
-unsafe impl crate::sync::aref::AlwaysRefCounted for Device {
+unsafe impl RefCounted for Device {
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
unsafe { bindings::pci_dev_get(self.as_raw()) };
@@ -493,6 +497,10 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Device>` from a
+// `&Device`.
+unsafe impl AlwaysRefCounted for Device {}
+
impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
fn as_ref(&self) -> &device::Device<Ctx> {
// SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid
diff --git a/rust/kernel/pid_namespace.rs b/rust/kernel/pid_namespace.rs
index 979a9718f153d..067f68b99e8c5 100644
--- a/rust/kernel/pid_namespace.rs
+++ b/rust/kernel/pid_namespace.rs
@@ -7,7 +7,14 @@
//! C header: [`include/linux/pid_namespace.h`](srctree/include/linux/pid_namespace.h) and
//! [`include/linux/pid.h`](srctree/include/linux/pid.h)
-use crate::{bindings, sync::aref::AlwaysRefCounted, types::Opaque};
+use crate::{
+ bindings,
+ sync::aref::RefCounted,
+ types::{
+ AlwaysRefCounted,
+ Opaque, //
+ }, //
+};
use core::ptr;
/// Wraps the kernel's `struct pid_namespace`. Thread safe.
@@ -41,7 +48,7 @@ pub unsafe fn from_ptr<'a>(ptr: *const bindings::pid_namespace) -> &'a Self {
}
// SAFETY: Instances of `PidNamespace` are always reference-counted.
-unsafe impl AlwaysRefCounted for PidNamespace {
+unsafe impl RefCounted for PidNamespace {
#[inline]
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference means that the refcount is nonzero.
@@ -55,6 +62,10 @@ unsafe fn dec_ref(obj: ptr::NonNull<PidNamespace>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<PidNamespace>` from
+// a `&PidNamespace`.
+unsafe impl AlwaysRefCounted for PidNamespace {}
+
// SAFETY:
// - `PidNamespace::dec_ref` can be called from any thread.
// - It is okay to send ownership of `PidNamespace` across thread boundaries.
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 9b362e0495d32..0ba676445b06d 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -27,6 +27,10 @@
},
of,
prelude::*,
+ sync::aref::{
+ AlwaysRefCounted,
+ RefCounted, //
+ },
types::Opaque,
ThisModule, //
};
@@ -518,7 +522,7 @@ pub fn optional_irq_by_name(&self, name: &CStr) -> Result<IrqRequest<'_>> {
impl<'a> crate::dma::Device<'a> for Device<device::Core<'a>> {}
// SAFETY: Instances of `Device` are always reference-counted.
-unsafe impl crate::sync::aref::AlwaysRefCounted for Device {
+unsafe impl RefCounted for Device {
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
unsafe { bindings::get_device(self.as_ref().as_raw()) };
@@ -530,6 +534,10 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Device>` from a
+// `&Device`.
+unsafe impl AlwaysRefCounted for Device {}
+
impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
fn as_ref(&self) -> &device::Device<Ctx> {
// SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid
diff --git a/rust/kernel/pwm.rs b/rust/kernel/pwm.rs
index 6c9d667009ef7..2d1cd74dd98e1 100644
--- a/rust/kernel/pwm.rs
+++ b/rust/kernel/pwm.rs
@@ -13,7 +13,11 @@
devres,
error::{self, to_result},
prelude::*,
- sync::aref::{ARef, AlwaysRefCounted},
+ sync::aref::{
+ ARef,
+ AlwaysRefCounted,
+ RefCounted, //
+ },
types::Opaque, //
};
use core::{
@@ -629,7 +633,7 @@ pub fn new<'a>(
}
// SAFETY: Implements refcounting for `Chip` using the embedded `struct device`.
-unsafe impl<T: PwmOps> AlwaysRefCounted for Chip<T> {
+unsafe impl<T: PwmOps> RefCounted for Chip<T> {
#[inline]
fn inc_ref(&self) {
// SAFETY: `self.0.get()` points to a valid `pwm_chip` because `self` exists.
@@ -647,6 +651,10 @@ unsafe fn dec_ref(obj: NonNull<Chip<T>>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Chip<T>>` from a
+// `&Chip<T>`.
+unsafe impl<T: PwmOps> AlwaysRefCounted for Chip<T> {}
+
// SAFETY: `Chip` is a wrapper around `*mut bindings::pwm_chip`. The underlying C
// structure's state is managed and synchronized by the kernel's device model
// and PWM core locking mechanisms. Therefore, it is safe to move the `Chip`
diff --git a/rust/kernel/sync/aref.rs b/rust/kernel/sync/aref.rs
index 3bd5eb8a1a526..fb7466a362741 100644
--- a/rust/kernel/sync/aref.rs
+++ b/rust/kernel/sync/aref.rs
@@ -24,11 +24,9 @@
ptr::NonNull, //
};
-/// Types that are _always_ reference counted.
+/// Types that are internally reference counted.
///
/// It allows such types to define their own custom ref increment and decrement functions.
-/// Additionally, it allows users to convert from a shared reference `&T` to an owned reference
-/// [`ARef<T>`].
///
/// This is usually implemented by wrappers to existing structures on the C side of the code. For
/// Rust code, the recommendation is to use [`Arc`](crate::sync::Arc) to create reference-counted
@@ -45,9 +43,8 @@
/// at least until matching decrements are performed.
///
/// Implementers must also ensure that all instances are reference-counted. (Otherwise they
-/// won't be able to honour the requirement that [`AlwaysRefCounted::inc_ref`] keep the object
-/// alive.)
-pub unsafe trait AlwaysRefCounted {
+/// won't be able to honour the requirement that [`RefCounted::inc_ref`] keep the object alive.)
+pub unsafe trait RefCounted {
/// Increments the reference count on the object.
fn inc_ref(&self);
@@ -60,11 +57,27 @@ pub unsafe trait AlwaysRefCounted {
/// Callers must ensure that there was a previous matching increment to the reference count,
/// and that the object is no longer used after its reference count is decremented (as it may
/// result in the object being freed), unless the caller owns another increment on the refcount
- /// (e.g., it calls [`AlwaysRefCounted::inc_ref`] twice, then calls
- /// [`AlwaysRefCounted::dec_ref`] once).
+ /// (e.g., it calls [`RefCounted::inc_ref`] twice, then calls [`RefCounted::dec_ref`] once).
unsafe fn dec_ref(obj: NonNull<Self>);
}
+/// Always reference-counted type.
+///
+/// It allows deriving a counted reference [`ARef<T>`] from a `&T`.
+///
+/// This provides some convenience, but it allows "escaping" borrow checks on `&T`. As it
+/// complicates attempts to ensure that a reference to T is unique, it is optional to provide for
+/// [`RefCounted`] types. See *Safety* below.
+///
+/// # Safety
+///
+/// Implementers must ensure that no safety invariants are violated by upgrading an `&T` to an
+/// [`ARef<T>`]. In particular that implies [`AlwaysRefCounted`] and [`crate::types::Ownable`]
+/// cannot be implemented for the same type, as this would allow violating the uniqueness guarantee
+/// of [`crate::types::Owned<T>`] by dereferencing it into an `&T` and obtaining an [`ARef`] from
+/// that.
+pub unsafe trait AlwaysRefCounted: RefCounted {}
+
/// An owned reference to an always-reference-counted object.
///
/// The object's reference count is automatically decremented when an instance of [`ARef`] is
@@ -75,7 +88,7 @@ pub unsafe trait AlwaysRefCounted {
///
/// The pointer stored in `ptr` is non-null and valid for the lifetime of the [`ARef`] instance. In
/// particular, the [`ARef`] instance owns an increment on the underlying object's reference count.
-pub struct ARef<T: AlwaysRefCounted> {
+pub struct ARef<T: RefCounted> {
ptr: NonNull<T>,
_p: PhantomData<T>,
}
@@ -84,19 +97,19 @@ pub struct ARef<T: AlwaysRefCounted> {
// it effectively means sharing `&T` (which is safe because `T` is `Sync`); additionally, it needs
// `T` to be `Send` because any thread that has an `ARef<T>` may ultimately access `T` using a
// mutable reference, for example, when the reference count reaches zero and `T` is dropped.
-unsafe impl<T: AlwaysRefCounted + Sync + Send> Send for ARef<T> {}
+unsafe impl<T: RefCounted + Sync + Send> Send for ARef<T> {}
// SAFETY: It is safe to send `&ARef<T>` to another thread when the underlying `T` is `Sync`
// because it effectively means sharing `&T` (which is safe because `T` is `Sync`); additionally,
// it needs `T` to be `Send` because any thread that has a `&ARef<T>` may clone it and get an
// `ARef<T>` on that thread, so the thread may ultimately access `T` using a mutable reference, for
// example, when the reference count reaches zero and `T` is dropped.
-unsafe impl<T: AlwaysRefCounted + Sync + Send> Sync for ARef<T> {}
+unsafe impl<T: RefCounted + Sync + Send> Sync for ARef<T> {}
// Even if `T` is pinned, pointers to `T` can still move.
-impl<T: AlwaysRefCounted> Unpin for ARef<T> {}
+impl<T: RefCounted> Unpin for ARef<T> {}
-impl<T: AlwaysRefCounted> ARef<T> {
+impl<T: RefCounted> ARef<T> {
/// Creates a new instance of [`ARef`].
///
/// It takes over an increment of the reference count on the underlying object.
@@ -125,12 +138,12 @@ pub unsafe fn from_raw(ptr: NonNull<T>) -> Self {
///
/// ```
/// use core::ptr::NonNull;
- /// use kernel::sync::aref::{ARef, AlwaysRefCounted};
+ /// use kernel::sync::aref::{ARef, RefCounted};
///
/// struct Empty {}
///
/// # // SAFETY: TODO.
- /// unsafe impl AlwaysRefCounted for Empty {
+ /// unsafe impl RefCounted for Empty {
/// fn inc_ref(&self) {}
/// unsafe fn dec_ref(_obj: NonNull<Self>) {}
/// }
@@ -148,7 +161,7 @@ pub fn into_raw(me: Self) -> NonNull<T> {
}
}
-impl<T: AlwaysRefCounted> Clone for ARef<T> {
+impl<T: RefCounted> Clone for ARef<T> {
fn clone(&self) -> Self {
self.inc_ref();
// SAFETY: We just incremented the refcount above.
@@ -156,7 +169,7 @@ fn clone(&self) -> Self {
}
}
-impl<T: AlwaysRefCounted> Deref for ARef<T> {
+impl<T: RefCounted> Deref for ARef<T> {
type Target = T;
fn deref(&self) -> &Self::Target {
@@ -173,7 +186,7 @@ fn from(b: &T) -> Self {
}
}
-impl<T: AlwaysRefCounted> Drop for ARef<T> {
+impl<T: RefCounted> Drop for ARef<T> {
fn drop(&mut self) {
// SAFETY: The type invariants guarantee that the `ARef` owns the reference we're about to
// decrement.
@@ -183,19 +196,19 @@ fn drop(&mut self) {
impl<T, U> PartialEq<ARef<U>> for ARef<T>
where
- T: AlwaysRefCounted + PartialEq<U>,
- U: AlwaysRefCounted,
+ T: RefCounted + PartialEq<U>,
+ U: RefCounted,
{
#[inline]
fn eq(&self, other: &ARef<U>) -> bool {
T::eq(&**self, &**other)
}
}
-impl<T: AlwaysRefCounted + Eq> Eq for ARef<T> {}
+impl<T: RefCounted + Eq> Eq for ARef<T> {}
impl<T, U> PartialEq<&'_ U> for ARef<T>
where
- T: AlwaysRefCounted + PartialEq<U>,
+ T: RefCounted + PartialEq<U>,
{
#[inline]
fn eq(&self, other: &&U) -> bool {
diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs
index 38273f4eedb51..6259430b0ca31 100644
--- a/rust/kernel/task.rs
+++ b/rust/kernel/task.rs
@@ -10,7 +10,12 @@
pid_namespace::PidNamespace,
prelude::*,
sync::aref::ARef,
- types::{NotThreadSafe, Opaque},
+ types::{
+ AlwaysRefCounted,
+ NotThreadSafe,
+ Opaque,
+ RefCounted, //
+ },
};
use core::{
ops::Deref,
@@ -347,7 +352,7 @@ pub fn group_leader(&self) -> &Task {
}
// SAFETY: The type invariants guarantee that `Task` is always refcounted.
-unsafe impl crate::sync::aref::AlwaysRefCounted for Task {
+unsafe impl RefCounted for Task {
#[inline]
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference means that the refcount is nonzero.
@@ -361,6 +366,10 @@ unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Task>` from a
+// `&Task`.
+unsafe impl AlwaysRefCounted for Task {}
+
impl PartialEq for Task {
#[inline]
fn eq(&self, other: &Self) -> bool {
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index c41eab0ec983c..5ef763717e59a 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -15,9 +15,15 @@
pub mod for_lt;
pub use for_lt::ForLt;
-pub use crate::owned::{
- Ownable,
- Owned, //
+pub use crate::{
+ owned::{
+ Ownable,
+ Owned, //
+ },
+ sync::aref::{
+ AlwaysRefCounted,
+ RefCounted, //
+ }, //
};
/// Used to transfer ownership to and from foreign (non-Rust) languages.
diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
index 7aff0c82d0afc..59350c6b0df2a 100644
--- a/rust/kernel/usb.rs
+++ b/rust/kernel/usb.rs
@@ -18,7 +18,10 @@
to_result, //
},
prelude::*,
- sync::aref::AlwaysRefCounted,
+ sync::aref::{
+ AlwaysRefCounted,
+ RefCounted, //
+ },
types::Opaque,
ThisModule, //
};
@@ -392,7 +395,7 @@ fn as_ref(&self) -> &Device {
}
// SAFETY: Instances of `Interface` are always reference-counted.
-unsafe impl AlwaysRefCounted for Interface {
+unsafe impl RefCounted for Interface {
fn inc_ref(&self) {
// SAFETY: The invariants of `Interface` guarantee that `self.as_raw()`
// returns a valid `struct usb_interface` pointer, for which we will
@@ -406,6 +409,10 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Interface>` from a
+// `&Interface`.
+unsafe impl AlwaysRefCounted for Interface {}
+
// SAFETY: A `Interface` is always reference-counted and can be released from any thread.
unsafe impl Send for Interface {}
@@ -443,7 +450,7 @@ fn as_raw(&self) -> *mut bindings::usb_device {
kernel::impl_device_context_into_aref!(Device);
// SAFETY: Instances of `Device` are always reference-counted.
-unsafe impl AlwaysRefCounted for Device {
+unsafe impl RefCounted for Device {
fn inc_ref(&self) {
// SAFETY: The invariants of `Device` guarantee that `self.as_raw()`
// returns a valid `struct usb_device` pointer, for which we will
@@ -457,6 +464,10 @@ unsafe fn dec_ref(obj: NonNull<Self>) {
}
}
+// SAFETY: We do not implement `Ownable`, thus it is okay to obtain an `ARef<Device>` from a
+// `&Device`.
+unsafe impl AlwaysRefCounted for Device {}
+
impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
fn as_ref(&self) -> &device::Device<Ctx> {
// SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid
--
2.51.2
^ permalink raw reply related
* [PATCH v18 1/8] rust: alloc: add `KBox::into_non_null`
From: Andreas Hindborg @ 2026-06-25 10:15 UTC (permalink / raw)
To: Danilo Krummrich, Lorenzo Stoakes, Vlastimil Babka,
Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda, Boqun Feng,
Gary Guo, Björn Roy Baron, Benno Lossin, Alice Ryhl,
Trevor Gross, Daniel Almeida, Tamir Duberstein, Alexandre Courbot,
Onur Özkan, Lyude Paul, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Rafael J. Wysocki, Dave Ertman, Ira Weiny,
Leon Romanovsky, Paul Moore, Serge Hallyn, David Airlie,
Simona Vetter, Alexander Viro, Jan Kara, Igor Korotin,
Viresh Kumar, Nishanth Menon, Stephen Boyd, Bjorn Helgaas,
Krzysztof Wilczyński, Pavel Tikhomirov, Michal Wilczynski
Cc: Andreas Hindborg, Philipp Stanner, rust-for-linux, linux-kernel,
linux-mm, driver-core, linux-block, linux-security-module,
dri-devel, linux-fsdevel, linux-pm, linux-pci, linux-pwm
In-Reply-To: <20260625-unique-ref-v18-0-4e06b5896d47@kernel.org>
Add a method to consume a `Box<T, A>` and return a `NonNull<T>`. This
is a convenience wrapper around `Self::into_raw` for callers that need
a `NonNull` pointer rather than a raw pointer.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
---
rust/kernel/alloc/kbox.rs | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs
index 35d1e015848dd..d534e8adcf7b3 100644
--- a/rust/kernel/alloc/kbox.rs
+++ b/rust/kernel/alloc/kbox.rs
@@ -211,6 +211,15 @@ pub fn leak<'a>(b: Self) -> &'a mut T {
// which points to an initialized instance of `T`.
unsafe { &mut *Box::into_raw(b) }
}
+
+ /// Consumes the `Box<T,A>` and returns a `NonNull<T>`.
+ ///
+ /// Like [`Self::into_raw`], but returns a `NonNull`.
+ #[inline]
+ pub fn into_non_null(b: Self) -> NonNull<T> {
+ // SAFETY: `KBox::into_raw` returns a valid pointer.
+ unsafe { NonNull::new_unchecked(Self::into_raw(b)) }
+ }
}
impl<T, A> Box<MaybeUninit<T>, A>
--
2.51.2
^ permalink raw reply related
* [PATCH v18 3/8] rust: implement `ForeignOwnable` for `Owned`
From: Andreas Hindborg @ 2026-06-25 10:15 UTC (permalink / raw)
To: Danilo Krummrich, Lorenzo Stoakes, Vlastimil Babka,
Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda, Boqun Feng,
Gary Guo, Björn Roy Baron, Benno Lossin, Alice Ryhl,
Trevor Gross, Daniel Almeida, Tamir Duberstein, Alexandre Courbot,
Onur Özkan, Lyude Paul, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Rafael J. Wysocki, Dave Ertman, Ira Weiny,
Leon Romanovsky, Paul Moore, Serge Hallyn, David Airlie,
Simona Vetter, Alexander Viro, Jan Kara, Igor Korotin,
Viresh Kumar, Nishanth Menon, Stephen Boyd, Bjorn Helgaas,
Krzysztof Wilczyński, Pavel Tikhomirov, Michal Wilczynski
Cc: Andreas Hindborg, Philipp Stanner, rust-for-linux, linux-kernel,
linux-mm, driver-core, linux-block, linux-security-module,
dri-devel, linux-fsdevel, linux-pm, linux-pci, linux-pwm
In-Reply-To: <20260625-unique-ref-v18-0-4e06b5896d47@kernel.org>
Implement `ForeignOwnable` for `Owned<T>`. This allows use of `Owned<T>` in
places such as the `XArray`.
Note that `T` does not need to implement `ForeignOwnable` for `Owned<T>` to
implement `ForeignOwnable`.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/owned.rs | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)
diff --git a/rust/kernel/owned.rs b/rust/kernel/owned.rs
index 7fe9ec3e55126..9c92d4a83cc1b 100644
--- a/rust/kernel/owned.rs
+++ b/rust/kernel/owned.rs
@@ -15,6 +15,8 @@
ptr::NonNull, //
};
+use kernel::types::ForeignOwnable;
+
/// Types that specify their own way of performing allocation and destruction. Typically, this trait
/// is implemented on types from the C side.
///
@@ -186,3 +188,54 @@ fn drop(&mut self) {
unsafe { T::release(self.ptr) };
}
}
+
+// SAFETY: We derive the pointer to `T` from a valid `T`, so the returned
+// pointer satisfy alignment requirements of `T`.
+unsafe impl<T: Ownable> ForeignOwnable for Owned<T> {
+ const FOREIGN_ALIGN: usize = core::mem::align_of::<T>();
+
+ type Borrowed<'a>
+ = &'a T
+ where
+ Self: 'a;
+ type BorrowedMut<'a>
+ = Pin<&'a mut T>
+ where
+ Self: 'a;
+
+ #[inline]
+ fn into_foreign(self) -> *mut kernel::ffi::c_void {
+ let ptr = self.ptr.as_ptr().cast();
+ core::mem::forget(self);
+ ptr
+ }
+
+ #[inline]
+ unsafe fn from_foreign(ptr: *mut kernel::ffi::c_void) -> Self {
+ // INVARIANT: By the function safety contract, `ptr` was returned by `into_foreign`, which
+ // gave up exclusive ownership of a valid, pinned `T`; we retake that ownership here.
+ Self {
+ // SAFETY: By function safety contract, `ptr` came from
+ // `into_foreign` and cannot be null.
+ ptr: unsafe { NonNull::new_unchecked(ptr.cast()) },
+ }
+ }
+
+ #[inline]
+ unsafe fn borrow<'a>(ptr: *mut kernel::ffi::c_void) -> Self::Borrowed<'a> {
+ // SAFETY: By function safety requirements, `ptr` is valid for use as a
+ // reference for `'a`.
+ unsafe { &*ptr.cast() }
+ }
+
+ #[inline]
+ unsafe fn borrow_mut<'a>(ptr: *mut kernel::ffi::c_void) -> Self::BorrowedMut<'a> {
+ // SAFETY: By function safety requirements, `ptr` is valid for use as a
+ // unique reference for `'a`.
+ let inner = unsafe { &mut *ptr.cast() };
+
+ // SAFETY: We never move out of inner, and we do not hand out mutable
+ // references when `T: !Unpin`.
+ unsafe { Pin::new_unchecked(inner) }
+ }
+}
--
2.51.2
^ permalink raw reply related
* [PATCH v18 0/8] rust: add `Ownable` trait and `Owned` type
From: Andreas Hindborg @ 2026-06-25 10:15 UTC (permalink / raw)
To: Danilo Krummrich, Lorenzo Stoakes, Vlastimil Babka,
Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda, Boqun Feng,
Gary Guo, Björn Roy Baron, Benno Lossin, Alice Ryhl,
Trevor Gross, Daniel Almeida, Tamir Duberstein, Alexandre Courbot,
Onur Özkan, Lyude Paul, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Rafael J. Wysocki, Dave Ertman, Ira Weiny,
Leon Romanovsky, Paul Moore, Serge Hallyn, David Airlie,
Simona Vetter, Alexander Viro, Jan Kara, Igor Korotin,
Viresh Kumar, Nishanth Menon, Stephen Boyd, Bjorn Helgaas,
Krzysztof Wilczyński, Pavel Tikhomirov, Michal Wilczynski
Cc: Andreas Hindborg, Philipp Stanner, rust-for-linux, linux-kernel,
linux-mm, driver-core, linux-block, linux-security-module,
dri-devel, linux-fsdevel, linux-pm, linux-pci, linux-pwm,
Asahi Lina, Oliver Mangold, Viresh Kumar, Boqun Feng, Asahi Lina,
Igor Korotin, Andreas Hindborg
Add a new trait `Ownable` and type `Owned` for types that specify their
own way of performing allocation and destruction. This is useful for
types from the C side.
Implement `ForeignOwnable` for `Owned`.
Convert `Page` to be `Ownable` and add a `from_raw` method.
Add the trait `OwnableRefCounted` that allows conversion between
`ARef` and `Owned`. This is analogous to conversion between `Arc` and
`UniqueArc`.
Patches 1-4 implement `Ownable` and applies it to `Page`. These patches
can be merged on their own.
Patches 5-7 add `Ownable` -> `ARef` interop and can be merged later if
consensus on their shape cannot be reached.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
Changes in v18:
- Rebase on `rust-next` (2026-06-24).
- Drop the `'static` bound on `ForeignOwnable for Owned` (Gary).
- Make `Ownable::release` take a raw pointer instead of `&mut self` (Alice, Sashiko).
- Drop `types::ARef` re-export (Alice).
- Drop unneeded `#[repr(transparent)]` on `Owned` (Gary).
- Fix `FOREIGN_ALIGN` for `Owned` to report the pointee alignment (Sashiko).
- Remove `BorrowedPage`; use `&Page` directly (Alice).
- Update Rust Binder for the `Owned<Page>` conversion (Alice).
- Update `pwm.rs` for the `RefCounted`/`AlwaysRefCounted` split (Sashiko).
- Fix documentation nits: missing `// INVARIANT:` comments, stale `Page` docs, and a stray `mut` (Sashiko).
- Expand the `use` statements touched by the rename patch to the multi-line style (Onur).
- Link to v17: https://msgid.link/20260604-unique-ref-v17-0-7b4c3d2930b9@kernel.org
Changes in v17:
- Rebase on v7.1-rc2.
- Reorder patches so that `Ownable` can merge without `OwnableRefCounted` (Alice).
- Add `#[inline]` directives to short functions added by the series (Gary).
- Link to v16: https://msgid.link/20260224-unique-ref-v16-0-c21afcb118d3@kernel.org
Changes in v16:
- Simplify pointer to reference cast in `Page::from_raw`.
- Use `NonNull<Page>` rather than `Owned<Page>` for `BorrowedPage` internals.
- Use "convertible to reference" wording when converting pointers to references.
- Fix formatting for `Page::from_raw` docs.
- Leave imports alone when adding safety comment to aref example.
- Use `KBox::into_nonnull` for examples.
- Add patch for `KBox::into_nonnull`.
- Change invariants and safety comments of `Ownable` and make the trait safe.
- Make `Ownable::release` take a mutable reference.
- Fix error handling in example for `Ownable`
- Link to v15: https://msgid.link/20260220-unique-ref-v15-0-893ed86b06cc@kernel.org
Changes in v15:
- Update series with original SoB's.
- Rename `AlwaysRefCounted` in `kernel::usb`.
- Rename `Owned::get_pin_mut` to `Owned::as_pin_mut`.
- Link to v14: https://msgid.link/20260204-unique-ref-v14-0-17cb29ebacbb@kernel.org
Changes in v14:
- Rebase on v6.19-rc7.
- Rewrite cover letter.
- Update documentation and safety comments based on v13 feedback.
- Update commit messages.
- Reorder implementation blocks in owned.rs.
- Update example in owned.rs to use try operator rather than `expect`.
- Reformat use statements.
- Add patch: rust: page: convert to `Ownable`.
- Add patch: rust: implement `ForeignOwnable` for `Owned`.
- Add patch: rust: page: add `from_raw()`.
- Link to v13: https://lore.kernel.org/r/20251117-unique-ref-v13-0-b5b243df1250@pm.me
Changes in v13:
- Rebase onto v6.18-rc1 (Andreas's work).
- Documentation and style fixes contributed by Andreas
- Link to v12: https://lore.kernel.org/r/20251001-unique-ref-v12-0-fa5c31f0c0c4@pm.me
Changes in v12:
-
- Rebase onto v6.17-rc1 (Andreas's work).
- moved kernel/types/ownable.rs to kernel/owned.rs
- Drop OwnableMut, make DerefMut depend on Unpin instead. I understood
ML discussion as that being okay, but probably needs further scrunity.
- Lots of more documentation changes suggested by reviewers.
- Usage example for Ownable/Owned.
- Link to v11: https://lore.kernel.org/r/20250618-unique-ref-v11-0-49eadcdc0aa6@pm.me
Changes in v11:
- Rework of documentation. I tried to honor all requests for changes "in
spirit" plus some clearifications and corrections of my own.
- Dropping `SimpleOwnedRefCounted` by request from Alice, as it creates a
potentially problematic blanket implementation (which a derive macro that
could be created later would not have).
- Dropping Miguel's "kbuild: provide `RUSTC_HAS_DO_NOT_RECOMMEND` symbol"
patch, as it is not needed anymore after dropping `SimpleOwnedRefCounted`.
(I can add it again, if it is considered useful anyway).
- Link to v10: https://lore.kernel.org/r/20250502-unique-ref-v10-0-25de64c0307f@pm.me
Changes in v10:
- Moved kernel/ownable.rs to kernel/types/ownable.rs
- Fixes in documentation / comments as suggested by Andreas Hindborg
- Added Reviewed-by comment for Andreas Hindborg
- Fix rustfmt of pid_namespace.rs
- Link to v9: https://lore.kernel.org/r/20250325-unique-ref-v9-0-e91618c1de26@pm.me
Changes in v9:
- Rebase onto v6.14-rc7
- Move Ownable/OwnedRefCounted/Ownable, etc., into separate module
- Documentation fixes to Ownable/OwnableMut/OwnableRefCounted
- Add missing SAFETY documentation to ARef example
- Link to v8: https://lore.kernel.org/r/20250313-unique-ref-v8-0-3082ffc67a31@pm.me
Changes in v8:
- Fix Co-developed-by and Suggested-by tags as suggested by Miguel and Boqun
- Some small documentation fixes in Owned/Ownable patch
- removing redundant trait constraint on DerefMut for Owned as suggested by Boqun Feng
- make SimpleOwnedRefCounted no longer implement RefCounted as suggested by Boqun Feng
- documentation for RefCounted as suggested by Boqun Feng
- Link to v7: https://lore.kernel.org/r/20250310-unique-ref-v7-0-4caddb78aa05@pm.me
Changes in v7:
- Squash patch to make Owned::from_raw/into_raw public into parent
- Added Signed-off-by to other people's commits
- Link to v6: https://lore.kernel.org/r/20250310-unique-ref-v6-0-1ff53558617e@pm.me
Changes in v6:
- Changed comments/formatting as suggested by Miguel Ojeda
- Included and used new config flag RUSTC_HAS_DO_NOT_RECOMMEND,
thus no changes to types.rs will be needed when the attribute
becomes available.
- Fixed commit message for Owned patch.
- Link to v5: https://lore.kernel.org/r/20250307-unique-ref-v5-0-bffeb633277e@pm.me
Changes in v5:
- Rebase the whole thing on top of the Ownable/Owned traits by Asahi Lina.
- Rename AlwaysRefCounted to RefCounted and make AlwaysRefCounted a
marker trait instead to allow to obtain an ARef<T> from an &T,
which (as Alice pointed out) is unsound when combined with UniqueRef/Owned.
- Change the Trait design and naming to implement this feature,
UniqueRef/UniqueRefCounted is dropped in favor of Ownable/Owned and
OwnableRefCounted is used to provide the functions to convert
between Owned and ARef.
- Link to v4: https://lore.kernel.org/r/20250305-unique-ref-v4-1-a8fdef7b1c2c@pm.me
Changes in v4:
- Just a minor change in naming by request from Andreas Hindborg,
try_shared_to_unique() -> try_from_shared(),
unique_to_shared() -> into_shared(),
which is more in line with standard Rust naming conventions.
- Link to v3: https://lore.kernel.org/r/Z8Wuud2UQX6Yukyr@mango
To: Danilo Krummrich <dakr@kernel.org>
To: Lorenzo Stoakes <ljs@kernel.org>
To: Vlastimil Babka <vbabka@kernel.org>
To: "Liam R. Howlett" <liam@infradead.org>
To: Uladzislau Rezki <urezki@gmail.com>
To: Miguel Ojeda <ojeda@kernel.org>
To: Boqun Feng <boqun@kernel.org>
To: Gary Guo <gary@garyguo.net>
To: Björn Roy Baron <bjorn3_gh@protonmail.com>
To: Benno Lossin <lossin@kernel.org>
To: Andreas Hindborg <a.hindborg@kernel.org>
To: Alice Ryhl <aliceryhl@google.com>
To: Trevor Gross <tmgross@umich.edu>
To: Daniel Almeida <daniel.almeida@collabora.com>
To: Tamir Duberstein <tamird@kernel.org>
To: Alexandre Courbot <acourbot@nvidia.com>
To: Onur Özkan <work@onurozkan.dev>
To: Lyude Paul <lyude@redhat.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Arve Hjønnevåg <arve@android.com>
To: Todd Kjos <tkjos@android.com>
To: Christian Brauner <brauner@kernel.org>
To: Carlos Llamas <cmllamas@google.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
To: Dave Ertman <david.m.ertman@intel.com>
To: Ira Weiny <ira.weiny@intel.com>
To: Leon Romanovsky <leon@kernel.org>
To: Paul Moore <paul@paul-moore.com>
To: Serge Hallyn <sergeh@kernel.org>
To: David Airlie <airlied@gmail.com>
To: Simona Vetter <simona@ffwll.ch>
To: Alexander Viro <viro@zeniv.linux.org.uk>
To: Jan Kara <jack@suse.cz>
To: Igor Korotin <igor.korotin@linux.dev>
To: Viresh Kumar <vireshk@kernel.org>
To: Nishanth Menon <nm@ti.com>
To: Stephen Boyd <sboyd@kernel.org>
To: Bjorn Helgaas <bhelgaas@google.com>
To: Krzysztof Wilczyński <kwilczynski@kernel.org>
To: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
To: Michal Wilczynski <m.wilczynski@samsung.com>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: rust-for-linux@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: driver-core@lists.linux.dev
Cc: linux-block@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-pwm@vger.kernel.org
---
Andreas Hindborg (3):
rust: alloc: add `KBox::into_non_null`
rust: implement `ForeignOwnable` for `Owned`
rust: page: add `from_raw()`
Asahi Lina (2):
rust: types: Add Ownable/Owned types
rust: page: convert to `Ownable`
Oliver Mangold (3):
rust: rename `AlwaysRefCounted` to `RefCounted`.
rust: Add missing SAFETY documentation for `ARef` example
rust: Add `OwnableRefCounted`
drivers/android/binder/page_range.rs | 10 +-
rust/kernel/alloc/allocator.rs | 19 +-
rust/kernel/alloc/allocator/iter.rs | 6 +-
rust/kernel/alloc/kbox.rs | 9 +
rust/kernel/auxiliary.rs | 10 +-
rust/kernel/block/mq/request.rs | 19 +-
rust/kernel/cred.rs | 16 +-
rust/kernel/device.rs | 12 +-
rust/kernel/device/property.rs | 11 +-
rust/kernel/drm/device.rs | 9 +-
rust/kernel/drm/gem/mod.rs | 16 +-
rust/kernel/fs/file.rs | 23 ++-
rust/kernel/i2c.rs | 13 +-
rust/kernel/lib.rs | 1 +
rust/kernel/mm.rs | 22 ++-
rust/kernel/mm/mmput_async.rs | 12 +-
rust/kernel/opp.rs | 16 +-
rust/kernel/owned.rs | 371 +++++++++++++++++++++++++++++++++++
rust/kernel/page.rs | 136 +++++--------
rust/kernel/pci.rs | 10 +-
rust/kernel/pid_namespace.rs | 15 +-
rust/kernel/platform.rs | 10 +-
rust/kernel/pwm.rs | 12 +-
rust/kernel/sync/aref.rs | 82 +++++---
rust/kernel/task.rs | 13 +-
rust/kernel/types.rs | 12 ++
rust/kernel/usb.rs | 17 +-
27 files changed, 721 insertions(+), 181 deletions(-)
---
base-commit: 43a393185e33e573a374c1d4f7ddf6481484ef8d
change-id: 20250305-unique-ref-29fcd675f9e9
Best regards,
--
Andreas Hindborg <a.hindborg@kernel.org>
^ permalink raw reply
* [PATCH v18 6/8] rust: Add missing SAFETY documentation for `ARef` example
From: Andreas Hindborg @ 2026-06-25 10:15 UTC (permalink / raw)
To: Danilo Krummrich, Lorenzo Stoakes, Vlastimil Babka,
Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda, Boqun Feng,
Gary Guo, Björn Roy Baron, Benno Lossin, Alice Ryhl,
Trevor Gross, Daniel Almeida, Tamir Duberstein, Alexandre Courbot,
Onur Özkan, Lyude Paul, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Rafael J. Wysocki, Dave Ertman, Ira Weiny,
Leon Romanovsky, Paul Moore, Serge Hallyn, David Airlie,
Simona Vetter, Alexander Viro, Jan Kara, Igor Korotin,
Viresh Kumar, Nishanth Menon, Stephen Boyd, Bjorn Helgaas,
Krzysztof Wilczyński, Pavel Tikhomirov, Michal Wilczynski
Cc: Andreas Hindborg, Philipp Stanner, rust-for-linux, linux-kernel,
linux-mm, driver-core, linux-block, linux-security-module,
dri-devel, linux-fsdevel, linux-pm, linux-pci, linux-pwm,
Oliver Mangold
In-Reply-To: <20260625-unique-ref-v18-0-4e06b5896d47@kernel.org>
From: Oliver Mangold <oliver.mangold@pm.me>
SAFETY comment in rustdoc example was just 'TODO'. Fixed.
Signed-off-by: Oliver Mangold <oliver.mangold@pm.me>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Co-developed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/sync/aref.rs | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/rust/kernel/sync/aref.rs b/rust/kernel/sync/aref.rs
index fb7466a362741..d0865aeb9371b 100644
--- a/rust/kernel/sync/aref.rs
+++ b/rust/kernel/sync/aref.rs
@@ -142,7 +142,9 @@ pub unsafe fn from_raw(ptr: NonNull<T>) -> Self {
///
/// struct Empty {}
///
- /// # // SAFETY: TODO.
+ /// // SAFETY: The `RefCounted` implementation for `Empty` does not count references and never
+ /// // frees the underlying object. Thus we can act as owning an increment on the refcount for
+ /// // the object that we pass to the newly created `ARef`.
/// unsafe impl RefCounted for Empty {
/// fn inc_ref(&self) {}
/// unsafe fn dec_ref(_obj: NonNull<Self>) {}
@@ -150,7 +152,7 @@ pub unsafe fn from_raw(ptr: NonNull<T>) -> Self {
///
/// let mut data = Empty {};
/// let ptr = NonNull::<Empty>::new(&mut data).unwrap();
- /// # // SAFETY: TODO.
+ /// // SAFETY: We keep `data` around longer than the `ARef`.
/// let data_ref: ARef<Empty> = unsafe { ARef::from_raw(ptr) };
/// let raw_ptr: NonNull<Empty> = ARef::into_raw(data_ref);
///
--
2.51.2
^ permalink raw reply related
* [PATCH v18 2/8] rust: types: Add Ownable/Owned types
From: Andreas Hindborg @ 2026-06-25 10:15 UTC (permalink / raw)
To: Danilo Krummrich, Lorenzo Stoakes, Vlastimil Babka,
Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda, Boqun Feng,
Gary Guo, Björn Roy Baron, Benno Lossin, Alice Ryhl,
Trevor Gross, Daniel Almeida, Tamir Duberstein, Alexandre Courbot,
Onur Özkan, Lyude Paul, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Rafael J. Wysocki, Dave Ertman, Ira Weiny,
Leon Romanovsky, Paul Moore, Serge Hallyn, David Airlie,
Simona Vetter, Alexander Viro, Jan Kara, Igor Korotin,
Viresh Kumar, Nishanth Menon, Stephen Boyd, Bjorn Helgaas,
Krzysztof Wilczyński, Pavel Tikhomirov, Michal Wilczynski
Cc: Andreas Hindborg, Philipp Stanner, rust-for-linux, linux-kernel,
linux-mm, driver-core, linux-block, linux-security-module,
dri-devel, linux-fsdevel, linux-pm, linux-pci, linux-pwm,
Asahi Lina, Oliver Mangold, Boqun Feng
In-Reply-To: <20260625-unique-ref-v18-0-4e06b5896d47@kernel.org>
From: Asahi Lina <lina+kernel@asahilina.net>
By analogy to `AlwaysRefCounted` and `ARef`, an `Ownable` type is a
(typically C FFI) type that *may* be owned by Rust, but need not be. Unlike
`AlwaysRefCounted`, this mechanism expects the reference to be unique
within Rust, and does not allow cloning.
Conceptually, this is similar to a `KBox<T>`, except that it delegates
resource management to the `T` instead of using a generic allocator.
[ om:
- Split code into separate file and `pub use` it from types.rs.
- Make from_raw() and into_raw() public.
- Remove OwnableMut, and make DerefMut dependent on Unpin instead.
- Usage example/doctest for Ownable/Owned.
- Fixes to documentation and commit message.
]
Link: https://lore.kernel.org/all/20250202-rust-page-v1-1-e3170d7fe55e@asahilina.net/
Signed-off-by: Asahi Lina <lina+kernel@asahilina.net>
Co-developed-by: Oliver Mangold <oliver.mangold@pm.me>
Signed-off-by: Oliver Mangold <oliver.mangold@pm.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
[ Andreas: Updated documentation, examples, and formatting. Change safety
requirements, safety comments. ]
Co-developed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/lib.rs | 1 +
rust/kernel/owned.rs | 188 +++++++++++++++++++++++++++++++++++++++++++++++
rust/kernel/sync/aref.rs | 5 ++
rust/kernel/types.rs | 5 ++
4 files changed, 199 insertions(+)
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 9512af7156df2..eb5256204a174 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -101,6 +101,7 @@
pub mod of;
#[cfg(CONFIG_PM_OPP)]
pub mod opp;
+pub mod owned;
pub mod page;
#[cfg(CONFIG_PCI)]
pub mod pci;
diff --git a/rust/kernel/owned.rs b/rust/kernel/owned.rs
new file mode 100644
index 0000000000000..7fe9ec3e55126
--- /dev/null
+++ b/rust/kernel/owned.rs
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Unique owned pointer types for objects with custom drop logic.
+//!
+//! These pointer types are useful for C-allocated objects which by API-contract
+//! are owned by Rust, but need to be freed through the C API.
+
+use core::{
+ mem::ManuallyDrop,
+ ops::{
+ Deref,
+ DerefMut, //
+ },
+ pin::Pin,
+ ptr::NonNull, //
+};
+
+/// Types that specify their own way of performing allocation and destruction. Typically, this trait
+/// is implemented on types from the C side.
+///
+/// Implementing this trait allows types to be referenced via the [`Owned<Self>`] pointer type. This
+/// is useful when it is desirable to tie the lifetime of the reference to an owned object, rather
+/// than pass around a bare reference. [`Ownable`] types can define custom drop logic that is
+/// executed when the owned reference [`Owned<Self>`] pointing to the object is dropped.
+///
+/// Note: The underlying object is not required to provide internal reference counting, because it
+/// represents a unique, owned reference. If reference counting (on the Rust side) is required,
+/// [`AlwaysRefCounted`](crate::sync::aref::AlwaysRefCounted) should be implemented.
+///
+/// # Examples
+///
+/// A minimal example implementation of [`Ownable`] and its usage with [`Owned`] looks like
+/// this:
+///
+/// ```
+/// # #![expect(clippy::disallowed_names)]
+/// # use core::cell::Cell;
+/// # use core::ptr::NonNull;
+/// # use kernel::sync::global_lock;
+/// # use kernel::alloc::{flags, kbox::KBox, AllocError};
+/// # use kernel::types::{Owned, Ownable};
+///
+/// // Let's count the allocations to see if freeing works.
+/// kernel::sync::global_lock! {
+/// // SAFETY: we call `init()` right below, before doing anything else.
+/// unsafe(uninit) static FOO_ALLOC_COUNT: Mutex<usize> = 0;
+/// }
+/// // SAFETY: We call `init()` only once, here.
+/// unsafe { FOO_ALLOC_COUNT.init() };
+///
+/// struct Foo;
+///
+/// impl Foo {
+/// fn new() -> Result<Owned<Self>> {
+/// // We are just using a `KBox` here to handle the actual allocation, as our `Foo` is
+/// // not actually a C-allocated object.
+/// let result = KBox::new(
+/// Foo {},
+/// flags::GFP_KERNEL,
+/// )?;
+/// let result = KBox::into_non_null(result);
+/// // Count new allocation
+/// *FOO_ALLOC_COUNT.lock() += 1;
+/// // SAFETY:
+/// // - We just allocated the `Self`, thus it is valid and we own it.
+/// // - We can transfer this ownership to the `from_raw` method.
+/// Ok(unsafe { Owned::from_raw(result) })
+/// }
+/// }
+///
+/// impl Ownable for Foo {
+/// unsafe fn release(this: NonNull<Self>) {
+/// // SAFETY: The [`KBox<Self>`] is still alive. We can pass ownership to the [`KBox`], as
+/// // by requirement on calling this function.
+/// drop(unsafe { KBox::from_raw(this.as_ptr()) });
+/// // Count released allocation
+/// *FOO_ALLOC_COUNT.lock() -= 1;
+/// }
+/// }
+///
+/// {
+/// let foo = Foo::new()?;
+/// assert!(*FOO_ALLOC_COUNT.lock() == 1);
+/// }
+/// // `foo` is out of scope now, so we expect no live allocations.
+/// assert!(*FOO_ALLOC_COUNT.lock() == 0);
+/// # Ok::<(), Error>(())
+/// ```
+pub trait Ownable {
+ /// Tear down this `Ownable`.
+ ///
+ /// Implementers of `Ownable` can use this function to clean up the use of `Self`. This can
+ /// include freeing the underlying object.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that they have exclusive ownership of the `Self` pointed to by `this`,
+ /// and that this ownership is transferred to the `release` method. `this` must not be used
+ /// after calling this method, as the underlying object may have been freed.
+ unsafe fn release(this: NonNull<Self>);
+}
+
+/// A mutable reference to an owned `T`.
+///
+/// The [`Ownable`] is automatically freed or released when an instance of [`Owned`] is
+/// dropped.
+///
+/// # Invariants
+///
+/// - Until `T::release` is called, this `Owned<T>` exclusively owns the underlying `T`.
+/// - The `T` value is pinned.
+pub struct Owned<T: Ownable> {
+ ptr: NonNull<T>,
+}
+
+impl<T: Ownable> Owned<T> {
+ /// Creates a new instance of [`Owned`].
+ ///
+ /// This function takes over ownership of the underlying object.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that:
+ /// - `ptr` points to a valid instance of `T`.
+ /// - Until `T::release` is called, the returned `Owned<T>` exclusively owns the underlying `T`.
+ #[inline]
+ pub unsafe fn from_raw(ptr: NonNull<T>) -> Self {
+ // INVARIANT: By function safety requirement we satisfy the first invariant of `Self`.
+ // We treat `T` as pinned from now on.
+ Self { ptr }
+ }
+
+ /// Consumes the [`Owned`], returning a raw pointer.
+ ///
+ /// This function does not drop the underlying `T`. When this function returns, ownership of the
+ /// underlying `T` is with the caller.
+ #[inline]
+ pub fn into_raw(me: Self) -> NonNull<T> {
+ ManuallyDrop::new(me).ptr
+ }
+
+ /// Get a pinned mutable reference to the data owned by this `Owned<T>`.
+ #[inline]
+ pub fn as_pin_mut(&mut self) -> Pin<&mut T> {
+ // SAFETY: The type invariants guarantee that the object is valid, and that we can safely
+ // return a mutable reference to it.
+ let unpinned = unsafe { self.ptr.as_mut() };
+
+ // SAFETY: By type invariant `T` is pinned.
+ unsafe { Pin::new_unchecked(unpinned) }
+ }
+}
+
+// SAFETY: It is safe to send an [`Owned<T>`] to another thread when the underlying `T` is [`Send`],
+// because of the ownership invariant. Sending an [`Owned<T>`] is equivalent to sending the `T`.
+unsafe impl<T: Ownable + Send> Send for Owned<T> {}
+
+// SAFETY: It is safe to send [`&Owned<T>`] to another thread when the underlying `T` is [`Sync`],
+// because of the ownership invariant. Sending an [`&Owned<T>`] is equivalent to sending the `&T`.
+unsafe impl<T: Ownable + Sync> Sync for Owned<T> {}
+
+impl<T: Ownable> Deref for Owned<T> {
+ type Target = T;
+
+ #[inline]
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: The type invariants guarantee that the object is valid.
+ unsafe { self.ptr.as_ref() }
+ }
+}
+
+impl<T: Ownable + Unpin> DerefMut for Owned<T> {
+ #[inline]
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ // SAFETY: The type invariants guarantee that the object is valid, and that we can safely
+ // return a mutable reference to it.
+ unsafe { self.ptr.as_mut() }
+ }
+}
+
+impl<T: Ownable> Drop for Owned<T> {
+ #[inline]
+ fn drop(&mut self) {
+ // SAFETY: By existence of `&mut self` we exclusively own `self` and the underlying `T`. As
+ // we are dropping `self`, we can transfer ownership of the `T` to the `release` method.
+ unsafe { T::release(self.ptr) };
+ }
+}
diff --git a/rust/kernel/sync/aref.rs b/rust/kernel/sync/aref.rs
index b721b2e00b986..3bd5eb8a1a526 100644
--- a/rust/kernel/sync/aref.rs
+++ b/rust/kernel/sync/aref.rs
@@ -34,6 +34,11 @@
/// Rust code, the recommendation is to use [`Arc`](crate::sync::Arc) to create reference-counted
/// instances of a type.
///
+/// Note: Implementing this trait allows types to be wrapped in an [`ARef<Self>`]. It requires an
+/// internal reference count and provides only shared references. If unique references are required
+/// [`Ownable`](crate::types::Ownable) should be implemented which allows types to be wrapped in an
+/// [`Owned<Self>`](crate::types::Owned).
+///
/// # Safety
///
/// Implementers must ensure that increments to the reference count keep the object alive in memory
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index ac316fd7b538f..c41eab0ec983c 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -15,6 +15,11 @@
pub mod for_lt;
pub use for_lt::ForLt;
+pub use crate::owned::{
+ Ownable,
+ Owned, //
+};
+
/// Used to transfer ownership to and from foreign (non-Rust) languages.
///
/// Ownership is transferred from Rust to a foreign language by calling [`Self::into_foreign`] and
--
2.51.2
^ permalink raw reply related
* [PATCH v18 8/8] rust: page: add `from_raw()`
From: Andreas Hindborg @ 2026-06-25 10:15 UTC (permalink / raw)
To: Danilo Krummrich, Lorenzo Stoakes, Vlastimil Babka,
Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda, Boqun Feng,
Gary Guo, Björn Roy Baron, Benno Lossin, Alice Ryhl,
Trevor Gross, Daniel Almeida, Tamir Duberstein, Alexandre Courbot,
Onur Özkan, Lyude Paul, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Rafael J. Wysocki, Dave Ertman, Ira Weiny,
Leon Romanovsky, Paul Moore, Serge Hallyn, David Airlie,
Simona Vetter, Alexander Viro, Jan Kara, Igor Korotin,
Viresh Kumar, Nishanth Menon, Stephen Boyd, Bjorn Helgaas,
Krzysztof Wilczyński, Pavel Tikhomirov, Michal Wilczynski
Cc: Andreas Hindborg, Philipp Stanner, rust-for-linux, linux-kernel,
linux-mm, driver-core, linux-block, linux-security-module,
dri-devel, linux-fsdevel, linux-pm, linux-pci, linux-pwm,
Andreas Hindborg
In-Reply-To: <20260625-unique-ref-v18-0-4e06b5896d47@kernel.org>
From: Andreas Hindborg <a.hindborg@samsung.com>
Add a method to `Page` that allows construction of an instance from `struct
page` pointer.
Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Onur Özkan <work@onurozkan.dev>
---
rust/kernel/page.rs | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/rust/kernel/page.rs b/rust/kernel/page.rs
index 6dc1c2395acaf..c88fda09ead5a 100644
--- a/rust/kernel/page.rs
+++ b/rust/kernel/page.rs
@@ -143,6 +143,20 @@ pub fn nid(&self) -> i32 {
unsafe { bindings::page_to_nid(self.as_ptr()) }
}
+ /// Create a `&Page` from a raw `struct page` pointer.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must be convertible to a shared reference with a lifetime of `'a`.
+ #[inline]
+ pub unsafe fn from_raw<'a>(ptr: *const bindings::page) -> &'a Self {
+ // INVARIANT: By the function safety requirements, `ptr` refers to a valid `struct page`, so
+ // the returned reference upholds the type invariant of `Page`.
+ // SAFETY: By function safety requirements, `ptr` is not null and is convertible to a shared
+ // reference.
+ unsafe { &*ptr.cast() }
+ }
+
/// Runs a piece of code with this page mapped to an address.
///
/// The page is unmapped when this call returns.
--
2.51.2
^ permalink raw reply related
* [PATCH v18 4/8] rust: page: convert to `Ownable`
From: Andreas Hindborg @ 2026-06-25 10:15 UTC (permalink / raw)
To: Danilo Krummrich, Lorenzo Stoakes, Vlastimil Babka,
Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda, Boqun Feng,
Gary Guo, Björn Roy Baron, Benno Lossin, Alice Ryhl,
Trevor Gross, Daniel Almeida, Tamir Duberstein, Alexandre Courbot,
Onur Özkan, Lyude Paul, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Rafael J. Wysocki, Dave Ertman, Ira Weiny,
Leon Romanovsky, Paul Moore, Serge Hallyn, David Airlie,
Simona Vetter, Alexander Viro, Jan Kara, Igor Korotin,
Viresh Kumar, Nishanth Menon, Stephen Boyd, Bjorn Helgaas,
Krzysztof Wilczyński, Pavel Tikhomirov, Michal Wilczynski
Cc: Andreas Hindborg, Philipp Stanner, rust-for-linux, linux-kernel,
linux-mm, driver-core, linux-block, linux-security-module,
dri-devel, linux-fsdevel, linux-pm, linux-pci, linux-pwm,
Asahi Lina
In-Reply-To: <20260625-unique-ref-v18-0-4e06b5896d47@kernel.org>
From: Asahi Lina <lina@asahilina.net>
This allows Page references to be returned as borrowed references,
without necessarily owning the struct page.
Remove `BorrowedPage` and update users to use `Owned<Page>`.
Signed-off-by: Asahi Lina <lina@asahilina.net>
[ Andreas: Fix formatting and add a safety comment, update users. ]
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/android/binder/page_range.rs | 10 +--
rust/kernel/alloc/allocator.rs | 19 +++---
rust/kernel/alloc/allocator/iter.rs | 6 +-
rust/kernel/page.rs | 122 +++++++++--------------------------
4 files changed, 46 insertions(+), 111 deletions(-)
diff --git a/drivers/android/binder/page_range.rs b/drivers/android/binder/page_range.rs
index e54a90e62402a..7941eb85b4ef4 100644
--- a/drivers/android/binder/page_range.rs
+++ b/drivers/android/binder/page_range.rs
@@ -33,7 +33,7 @@
sync::{aref::ARef, Mutex, SpinLock},
task::Pid,
transmute::FromBytes,
- types::Opaque,
+ types::{Opaque, Owned},
uaccess::UserSliceReader,
};
@@ -198,7 +198,7 @@ unsafe impl Send for Inner {}
#[repr(C)]
struct PageInfo {
lru: bindings::list_head,
- page: Option<Page>,
+ page: Option<Owned<Page>>,
range: *const ShrinkablePageRange,
}
@@ -206,7 +206,7 @@ impl PageInfo {
/// # Safety
///
/// The caller ensures that writing to `me.page` is ok, and that the page is not currently set.
- unsafe fn set_page(me: *mut PageInfo, page: Page) {
+ unsafe fn set_page(me: *mut PageInfo, page: Owned<Page>) {
// SAFETY: This pointer offset is in bounds.
let ptr = unsafe { &raw mut (*me).page };
@@ -229,13 +229,13 @@ unsafe fn get_page<'a>(me: *const PageInfo) -> Option<&'a Page> {
let ptr = unsafe { &raw const (*me).page };
// SAFETY: The pointer is valid for reading.
- unsafe { (*ptr).as_ref() }
+ unsafe { (*ptr).as_deref() }
}
/// # Safety
///
/// The caller ensures that writing to `me.page` is ok for the duration of 'a.
- unsafe fn take_page(me: *mut PageInfo) -> Option<Page> {
+ unsafe fn take_page(me: *mut PageInfo) -> Option<Owned<Page>> {
// SAFETY: This pointer offset is in bounds.
let ptr = unsafe { &raw mut (*me).page };
diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
index cd4203f27aed0..c7b9b069cf75d 100644
--- a/rust/kernel/alloc/allocator.rs
+++ b/rust/kernel/alloc/allocator.rs
@@ -169,7 +169,7 @@ unsafe fn realloc(
}
impl Vmalloc {
- /// Convert a pointer to a [`Vmalloc`] allocation to a [`page::BorrowedPage`].
+ /// Convert a pointer to a [`Vmalloc`] allocation to a [`Page`](page::Page) reference.
///
/// # Examples
///
@@ -202,20 +202,17 @@ impl Vmalloc {
///
/// - `ptr` must be a valid pointer to a [`Vmalloc`] allocation.
/// - `ptr` must remain valid for the entire duration of `'a`.
- pub unsafe fn to_page<'a>(ptr: NonNull<u8>) -> page::BorrowedPage<'a> {
+ pub unsafe fn to_page<'a>(ptr: NonNull<u8>) -> &'a page::Page {
// SAFETY: `ptr` is a valid pointer to `Vmalloc` memory.
let page = unsafe { bindings::vmalloc_to_page(ptr.as_ptr().cast()) };
- // SAFETY: `vmalloc_to_page` returns a valid pointer to a `struct page` for a valid pointer
- // to `Vmalloc` memory.
- let page = unsafe { NonNull::new_unchecked(page) };
-
// SAFETY:
- // - `page` is a valid pointer to a `struct page`, given that by the safety requirements of
- // this function `ptr` is a valid pointer to a `Vmalloc` allocation.
- // - By the safety requirements of this function `ptr` is valid for the entire lifetime of
- // `'a`.
- unsafe { page::BorrowedPage::from_raw(page) }
+ // - `vmalloc_to_page` returns a valid, non-null pointer to a `struct page` for a valid
+ // pointer to `Vmalloc` memory, given that by the safety requirements of this function
+ // `ptr` is a valid pointer to a `Vmalloc` allocation.
+ // - By the safety requirements of this function `ptr`, and hence the `struct page`, is
+ // valid for the entire lifetime of `'a`.
+ unsafe { &*page.cast() }
}
}
diff --git a/rust/kernel/alloc/allocator/iter.rs b/rust/kernel/alloc/allocator/iter.rs
index 02fda3ea5cae6..8dcc16ed89893 100644
--- a/rust/kernel/alloc/allocator/iter.rs
+++ b/rust/kernel/alloc/allocator/iter.rs
@@ -9,7 +9,7 @@
ptr::NonNull, //
};
-/// An [`Iterator`] of [`page::BorrowedPage`] items owned by a [`Vmalloc`] allocation.
+/// An [`Iterator`] of [`Page`](page::Page) references owned by a [`Vmalloc`] allocation.
///
/// # Guarantees
///
@@ -28,11 +28,11 @@ pub struct VmallocPageIter<'a> {
size: usize,
/// The current page index of the [`Iterator`].
index: usize,
- _p: PhantomData<page::BorrowedPage<'a>>,
+ _p: PhantomData<&'a page::Page>,
}
impl<'a> Iterator for VmallocPageIter<'a> {
- type Item = page::BorrowedPage<'a>;
+ type Item = &'a page::Page;
fn next(&mut self) -> Option<Self::Item> {
let offset = self.index.checked_mul(page::PAGE_SIZE)?;
diff --git a/rust/kernel/page.rs b/rust/kernel/page.rs
index 8affd8262891b..6dc1c2395acaf 100644
--- a/rust/kernel/page.rs
+++ b/rust/kernel/page.rs
@@ -12,16 +12,16 @@
code::*,
Result, //
},
+ types::{
+ Opaque,
+ Ownable,
+ Owned, //
+ },
uaccess::UserSliceReader, //
};
-use core::{
- marker::PhantomData,
- mem::ManuallyDrop,
- ops::Deref,
- ptr::{
- self,
- NonNull, //
- }, //
+use core::ptr::{
+ self,
+ NonNull, //
};
/// A bitwise shift for the page size.
@@ -65,93 +65,29 @@ pub const fn page_align(addr: usize) -> Option<usize> {
Some(sum & PAGE_MASK)
}
-/// Representation of a non-owning reference to a [`Page`].
-///
-/// This type provides a borrowed version of a [`Page`] that is owned by some other entity, e.g. a
-/// [`Vmalloc`] allocation such as [`VBox`].
-///
-/// # Example
-///
-/// ```
-/// # use kernel::{bindings, prelude::*};
-/// use kernel::page::{BorrowedPage, Page, PAGE_SIZE};
-/// # use core::{mem::MaybeUninit, ptr, ptr::NonNull };
-///
-/// fn borrow_page<'a>(vbox: &'a mut VBox<MaybeUninit<[u8; PAGE_SIZE]>>) -> BorrowedPage<'a> {
-/// let ptr = ptr::from_ref(&**vbox);
-///
-/// // SAFETY: `ptr` is a valid pointer to `Vmalloc` memory.
-/// let page = unsafe { bindings::vmalloc_to_page(ptr.cast()) };
-///
-/// // SAFETY: `vmalloc_to_page` returns a valid pointer to a `struct page` for a valid
-/// // pointer to `Vmalloc` memory.
-/// let page = unsafe { NonNull::new_unchecked(page) };
-///
-/// // SAFETY:
-/// // - `self.0` is a valid pointer to a `struct page`.
-/// // - `self.0` is valid for the entire lifetime of `self`.
-/// unsafe { BorrowedPage::from_raw(page) }
-/// }
-///
-/// let mut vbox = VBox::<[u8; PAGE_SIZE]>::new_uninit(GFP_KERNEL)?;
-/// let page = borrow_page(&mut vbox);
-///
-/// // SAFETY: There is no concurrent read or write to this page.
-/// unsafe { page.fill_zero_raw(0, PAGE_SIZE)? };
-/// # Ok::<(), Error>(())
-/// ```
-///
-/// # Invariants
-///
-/// The borrowed underlying pointer to a `struct page` is valid for the entire lifetime `'a`.
-///
-/// [`VBox`]: kernel::alloc::VBox
-/// [`Vmalloc`]: kernel::alloc::allocator::Vmalloc
-pub struct BorrowedPage<'a>(ManuallyDrop<Page>, PhantomData<&'a Page>);
-
-impl<'a> BorrowedPage<'a> {
- /// Constructs a [`BorrowedPage`] from a raw pointer to a `struct page`.
- ///
- /// # Safety
- ///
- /// - `ptr` must point to a valid `bindings::page`.
- /// - `ptr` must remain valid for the entire lifetime `'a`.
- pub unsafe fn from_raw(ptr: NonNull<bindings::page>) -> Self {
- let page = Page { page: ptr };
-
- // INVARIANT: The safety requirements guarantee that `ptr` is valid for the entire lifetime
- // `'a`.
- Self(ManuallyDrop::new(page), PhantomData)
- }
-}
-
-impl<'a> Deref for BorrowedPage<'a> {
- type Target = Page;
-
- fn deref(&self) -> &Self::Target {
- &self.0
- }
-}
-
-/// Trait to be implemented by types which provide an [`Iterator`] implementation of
-/// [`BorrowedPage`] items, such as [`VmallocPageIter`](kernel::alloc::allocator::VmallocPageIter).
+/// Trait to be implemented by types which provide an [`Iterator`] of [`Page`] references, such as
+/// [`VmallocPageIter`](kernel::alloc::allocator::VmallocPageIter).
pub trait AsPageIter {
/// The [`Iterator`] type, e.g. [`VmallocPageIter`](kernel::alloc::allocator::VmallocPageIter).
- type Iter<'a>: Iterator<Item = BorrowedPage<'a>>
+ type Iter<'a>: Iterator<Item = &'a Page>
where
Self: 'a;
- /// Returns an [`Iterator`] of [`BorrowedPage`] items over all pages owned by `self`.
+ /// Returns an [`Iterator`] of [`Page`] references over all pages owned by `self`.
fn page_iter(&mut self) -> Self::Iter<'_>;
}
-/// A pointer to a page that owns the page allocation.
+/// A `struct page`.
+///
+/// A `Page` is accessed through a shared reference or through an owning [`Owned<Page>`]; the latter
+/// frees the page allocation when it is dropped.
///
/// # Invariants
///
-/// The pointer is valid, and has ownership over the page.
+/// The `Page` is backed by a valid `struct page`.
+#[repr(transparent)]
pub struct Page {
- page: NonNull<bindings::page>,
+ page: Opaque<bindings::page>,
}
// SAFETY: Pages have no logic that relies on them staying on a given thread, so moving them across
@@ -185,19 +121,20 @@ impl Page {
/// # Ok::<(), kernel::alloc::AllocError>(())
/// ```
#[inline]
- pub fn alloc_page(flags: Flags) -> Result<Self, AllocError> {
+ pub fn alloc_page(flags: Flags) -> Result<Owned<Self>, AllocError> {
// SAFETY: Depending on the value of `gfp_flags`, this call may sleep. Other than that, it
// is always safe to call this method.
let page = unsafe { bindings::alloc_pages(flags.as_raw(), 0) };
let page = NonNull::new(page).ok_or(AllocError)?;
- // INVARIANT: We just successfully allocated a page, so we now have ownership of the newly
- // allocated page. We transfer that ownership to the new `Page` object.
- Ok(Self { page })
+ // SAFETY: We just successfully allocated a page, so we now have ownership of the newly
+ // allocated page. We transfer that ownership to the new `Owned<Page>` object.
+ // Since `Page` is transparent, we can cast the pointer directly.
+ Ok(unsafe { Owned::from_raw(page.cast()) })
}
/// Returns a raw pointer to the page.
pub fn as_ptr(&self) -> *mut bindings::page {
- self.page.as_ptr()
+ Opaque::cast_into(&self.page)
}
/// Get the node id containing this page.
@@ -372,10 +309,11 @@ pub unsafe fn copy_from_user_slice_raw(
}
}
-impl Drop for Page {
+impl Ownable for Page {
#[inline]
- fn drop(&mut self) {
- // SAFETY: By the type invariants, we have ownership of the page and can free it.
- unsafe { bindings::__free_pages(self.page.as_ptr(), 0) };
+ unsafe fn release(this: NonNull<Self>) {
+ // SAFETY: By the function safety requirements, we have ownership of the page and can free
+ // it. Since Page is transparent, we can cast the raw pointer directly.
+ unsafe { bindings::__free_pages(this.as_ptr().cast(), 0) };
}
}
--
2.51.2
^ permalink raw reply related
* [PATCH v18 7/8] rust: Add `OwnableRefCounted`
From: Andreas Hindborg @ 2026-06-25 10:15 UTC (permalink / raw)
To: Danilo Krummrich, Lorenzo Stoakes, Vlastimil Babka,
Liam R. Howlett, Uladzislau Rezki, Miguel Ojeda, Boqun Feng,
Gary Guo, Björn Roy Baron, Benno Lossin, Alice Ryhl,
Trevor Gross, Daniel Almeida, Tamir Duberstein, Alexandre Courbot,
Onur Özkan, Lyude Paul, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Rafael J. Wysocki, Dave Ertman, Ira Weiny,
Leon Romanovsky, Paul Moore, Serge Hallyn, David Airlie,
Simona Vetter, Alexander Viro, Jan Kara, Igor Korotin,
Viresh Kumar, Nishanth Menon, Stephen Boyd, Bjorn Helgaas,
Krzysztof Wilczyński, Pavel Tikhomirov, Michal Wilczynski
Cc: Andreas Hindborg, Philipp Stanner, rust-for-linux, linux-kernel,
linux-mm, driver-core, linux-block, linux-security-module,
dri-devel, linux-fsdevel, linux-pm, linux-pci, linux-pwm,
Oliver Mangold
In-Reply-To: <20260625-unique-ref-v18-0-4e06b5896d47@kernel.org>
From: Oliver Mangold <oliver.mangold@pm.me>
Types implementing one of these traits can safely convert between an
`ARef<T>` and an `Owned<T>`.
This is useful for types which generally are accessed through an `ARef`
but have methods which can only safely be called when the reference is
unique, like e.g. `block::mq::Request::end_ok()`.
Signed-off-by: Oliver Mangold <oliver.mangold@pm.me>
[ Andreas: Fix formatting, update documentation, fix error handling in
examples. ]
Co-developed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/owned.rs | 140 +++++++++++++++++++++++++++++++++++++++++++++--
rust/kernel/sync/aref.rs | 16 +++++-
rust/kernel/types.rs | 1 +
3 files changed, 151 insertions(+), 6 deletions(-)
diff --git a/rust/kernel/owned.rs b/rust/kernel/owned.rs
index e79936c00002c..bb4223c0f725a 100644
--- a/rust/kernel/owned.rs
+++ b/rust/kernel/owned.rs
@@ -14,20 +14,26 @@
pin::Pin,
ptr::NonNull, //
};
+use kernel::{
+ sync::aref::ARef,
+ types::RefCounted, //
+};
use kernel::types::ForeignOwnable;
/// Types that specify their own way of performing allocation and destruction. Typically, this trait
/// is implemented on types from the C side.
///
-/// Implementing this trait allows types to be referenced via the [`Owned<Self>`] pointer type. This
-/// is useful when it is desirable to tie the lifetime of the reference to an owned object, rather
-/// than pass around a bare reference. [`Ownable`] types can define custom drop logic that is
-/// executed when the owned reference [`Owned<Self>`] pointing to the object is dropped.
+/// Implementing this trait allows types to be referenced via the [`Owned<Self>`] pointer type.
+/// - This is useful when it is desirable to tie the lifetime of an object reference to an owned
+/// object, rather than pass around a bare reference.
+/// - [`Ownable`] types can define custom drop logic that is executed when the owned reference
+/// of type [`Owned<_>`] pointing to the object is dropped.
///
/// Note: The underlying object is not required to provide internal reference counting, because it
/// represents a unique, owned reference. If reference counting (on the Rust side) is required,
-/// [`RefCounted`](crate::types::RefCounted) should be implemented.
+/// [`RefCounted`] should be implemented. [`OwnableRefCounted`] should be implemented if conversion
+/// between unique and shared (reference counted) ownership is needed.
///
/// # Examples
///
@@ -239,3 +245,127 @@ unsafe fn borrow_mut<'a>(ptr: *mut kernel::ffi::c_void) -> Self::BorrowedMut<'a>
unsafe { Pin::new_unchecked(inner) }
}
}
+
+/// A trait for objects that can be wrapped in either one of the reference types [`Owned`] and
+/// [`ARef`].
+///
+/// # Examples
+///
+/// A minimal example implementation of [`OwnableRefCounted`], [`Ownable`] and its usage with
+/// [`ARef`] and [`Owned`] looks like this:
+///
+/// ```
+/// # #![expect(clippy::disallowed_names)]
+/// # use core::cell::Cell;
+/// # use core::ptr::NonNull;
+/// # use kernel::alloc::{flags, kbox::KBox, AllocError};
+/// # use kernel::sync::aref::{ARef, RefCounted};
+/// # use kernel::types::{Owned, Ownable, OwnableRefCounted};
+///
+/// // An internally refcounted struct for demonstration purposes.
+/// //
+/// // # Invariants
+/// //
+/// // - `refcount` is always non-zero for a valid object.
+/// // - `refcount` is >1 if there is more than one Rust reference to it.
+/// //
+/// struct Foo {
+/// refcount: Cell<usize>,
+/// }
+///
+/// impl Foo {
+/// fn new() -> Result<Owned<Self>> {
+/// // We are just using a `KBox` here to handle the actual allocation, as our `Foo` is
+/// // not actually a C-allocated object.
+/// // INVARIANT: We initialize `refcount` to 1, satisfying the invariants.
+/// let result = KBox::new(
+/// Foo {
+/// refcount: Cell::new(1),
+/// },
+/// flags::GFP_KERNEL,
+/// )?;
+/// let result = KBox::into_non_null(result);
+/// // SAFETY:
+/// // - We just allocated the `Self`, thus it is valid and we own it.
+/// // - We can transfer this ownership to the `from_raw` method.
+/// Ok(unsafe { Owned::from_raw(result) })
+/// }
+/// }
+///
+/// // SAFETY: We increment and decrement each time the respective function is called and only free
+/// // the `Foo` when the refcount reaches zero.
+/// unsafe impl RefCounted for Foo {
+/// fn inc_ref(&self) {
+/// self.refcount.replace(self.refcount.get() + 1);
+/// }
+///
+/// unsafe fn dec_ref(this: NonNull<Self>) {
+/// // SAFETY: By requirement on calling this function, the refcount is non-zero,
+/// // implying the underlying object is valid.
+/// let refcount = unsafe { &this.as_ref().refcount };
+/// let new_refcount = refcount.get() - 1;
+/// if new_refcount == 0 {
+/// // The `Foo` will be dropped when `KBox` goes out of scope.
+/// // SAFETY: The [`KBox<Foo>`] is still alive as the old refcount is 1. We can pass
+/// // ownership to the [`KBox`] as by requirement on calling this function,
+/// // the `Self` will no longer be used by the caller.
+/// unsafe { KBox::from_raw(this.as_ptr()) };
+/// } else {
+/// refcount.replace(new_refcount);
+/// }
+/// }
+/// }
+///
+/// impl OwnableRefCounted for Foo {
+/// fn try_from_shared(this: ARef<Self>) -> Result<Owned<Self>, ARef<Self>> {
+/// if this.refcount.get() == 1 {
+/// // SAFETY: The `Foo` is still alive and has no other Rust references as the refcount
+/// // is 1.
+/// Ok(unsafe { Owned::from_raw(ARef::into_raw(this)) })
+/// } else {
+/// Err(this)
+/// }
+/// }
+/// }
+///
+/// impl Ownable for Foo {
+/// unsafe fn release(this: NonNull<Self>) {
+/// // SAFETY: Using `dec_ref()` from [`RefCounted`] to release is okay, as the refcount is
+/// // always 1 for an [`Owned<Foo>`].
+/// unsafe { Foo::dec_ref(this) };
+/// }
+/// }
+///
+/// let foo = Foo::new()?;
+/// let foo = ARef::from(foo);
+/// {
+/// let bar = foo.clone();
+/// assert!(Owned::try_from(bar).is_err());
+/// }
+/// assert!(Owned::try_from(foo).is_ok());
+/// # Ok::<(), Error>(())
+/// ```
+pub trait OwnableRefCounted: RefCounted + Ownable + Sized {
+ /// Checks if the [`ARef`] is unique and converts it to an [`Owned`] if that is the case.
+ /// Otherwise it returns again an [`ARef`] to the same underlying object.
+ fn try_from_shared(this: ARef<Self>) -> Result<Owned<Self>, ARef<Self>>;
+
+ /// Converts the [`Owned`] into an [`ARef`].
+ #[inline]
+ fn into_shared(this: Owned<Self>) -> ARef<Self> {
+ // SAFETY: `Owned::into_raw` returns a pointer to a valid `Self`, and the `Owned` owned the
+ // reference count that we now transfer to the new `ARef`.
+ unsafe { ARef::from_raw(Owned::into_raw(this)) }
+ }
+}
+
+impl<T: OwnableRefCounted> TryFrom<ARef<T>> for Owned<T> {
+ type Error = ARef<T>;
+ /// Tries to convert the [`ARef`] to an [`Owned`] by calling
+ /// [`try_from_shared()`](OwnableRefCounted::try_from_shared). In case the [`ARef`] is not
+ /// unique, it returns again an [`ARef`] to the same underlying object.
+ #[inline]
+ fn try_from(b: ARef<T>) -> Result<Owned<T>, Self::Error> {
+ T::try_from_shared(b)
+ }
+}
diff --git a/rust/kernel/sync/aref.rs b/rust/kernel/sync/aref.rs
index d0865aeb9371b..77eb390139079 100644
--- a/rust/kernel/sync/aref.rs
+++ b/rust/kernel/sync/aref.rs
@@ -23,6 +23,10 @@
ops::Deref,
ptr::NonNull, //
};
+use kernel::types::{
+ OwnableRefCounted,
+ Owned, //
+};
/// Types that are internally reference counted.
///
@@ -35,7 +39,10 @@
/// Note: Implementing this trait allows types to be wrapped in an [`ARef<Self>`]. It requires an
/// internal reference count and provides only shared references. If unique references are required
/// [`Ownable`](crate::types::Ownable) should be implemented which allows types to be wrapped in an
-/// [`Owned<Self>`](crate::types::Owned).
+/// [`Owned<Self>`](crate::types::Owned). Implementing the trait
+/// [`OwnableRefCounted`] allows to convert between unique and
+/// shared references (i.e. [`Owned<Self>`](crate::types::Owned) and
+/// [`ARef<Self>`](crate::types::Owned)).
///
/// # Safety
///
@@ -188,6 +195,13 @@ fn from(b: &T) -> Self {
}
}
+impl<T: OwnableRefCounted> From<Owned<T>> for ARef<T> {
+ #[inline]
+ fn from(b: Owned<T>) -> Self {
+ T::into_shared(b)
+ }
+}
+
impl<T: RefCounted> Drop for ARef<T> {
fn drop(&mut self) {
// SAFETY: The type invariants guarantee that the `ARef` owns the reference we're about to
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index 5ef763717e59a..6aa760952cb63 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -18,6 +18,7 @@
pub use crate::{
owned::{
Ownable,
+ OwnableRefCounted,
Owned, //
},
sync::aref::{
--
2.51.2
^ permalink raw reply related
* Re: [PATCH] cpufreq: cppc: Reduce cppc delivered perf sampling jitter
From: Jie Zhan @ 2026-06-25 9:55 UTC (permalink / raw)
To: Jeremy Linton, linux-pm
Cc: sumitg, pierre.gondois, zhenglifeng1, viresh.kumar, leitao,
rafael, linux-kernel
In-Reply-To: <20260602212052.1278365-1-jeremy.linton@arm.com>
Hi Jeremy,
On 6/3/2026 5:20 AM, Jeremy Linton wrote:
> CPPC uses a pair of registers cycling at different frequencies to
> determine an accumulated performance level. For userspace reporting we
> want to convert this to an instantaneous CPU frequency, but over short
> time periods small errors caused by CPPC counter reads can cause
> fairly significant reported frequency variations even when the core
> CPU clock isn't changing.
>
> Reduce this by keeping a start sample fixed and retrying the end
> sample until the counter deltas are large enough to reduce short
> window error, or until adjacent delivered performance estimates are
> within the CPU's observed CPPC read noise floor.
>
> To begin, resample the initial pair a small fixed number of times
> looking for matching delivered performance deltas. This reduces the
> chance that a disturbed start sample anchors the rest of the
> calculation.
>
> Then look for an end sample while updating the noise floor from the
> best error seen between samples. The floor remains zero on systems
> with stable feedback reads, but lets noisy systems stop early once
> another retry is unlikely to improve the result. The retry loop is
> capped at 200 iterations, giving an ~20 usec explicit delay budget
> derived from ndelay(100).
>
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 68 ++++++++++++++++++++++++++++++----
> 1 file changed, 61 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 7e7f9dfb7a24..362c08def420 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -50,7 +50,7 @@ struct cppc_freq_invariance {
> static DEFINE_PER_CPU(struct cppc_freq_invariance, cppc_freq_inv);
> static struct kthread_worker *kworker_fie;
>
> -static int cppc_perf_from_fbctrs(u64 reference_perf,
> +static u64 cppc_perf_from_fbctrs(u64 reference_perf,
> struct cppc_perf_fb_ctrs *fb_ctrs_t0,
> struct cppc_perf_fb_ctrs *fb_ctrs_t1);
>
> @@ -750,7 +750,7 @@ static inline u64 get_delta(u64 t1, u64 t0)
> return (u32)t1 - (u32)t0;
> }
>
> -static int cppc_perf_from_fbctrs(u64 reference_perf,
> +static u64 cppc_perf_from_fbctrs(u64 reference_perf,
> struct cppc_perf_fb_ctrs *fb_ctrs_t0,
> struct cppc_perf_fb_ctrs *fb_ctrs_t1)
> {
> @@ -771,19 +771,71 @@ static int cppc_perf_from_fbctrs(u64 reference_perf,
> return (reference_perf * delta_delivered) / delta_reference;
> }
>
> -static int cppc_get_perf_ctrs_sample(int cpu,
> +/* CPPC read noise floor for early retry exit. */
> +static DEFINE_PER_CPU(u64, err_floor);
> +
> +#define CPPC_SAMPLE_MAX_RETRIES 200
> +
> +static int cppc_get_perf_ctrs_sample(int cpu, u64 ref,
> struct cppc_perf_fb_ctrs *fb_ctrs_t0,
> struct cppc_perf_fb_ctrs *fb_ctrs_t1)
> {
> int ret;
> + s64 last_delivered = 0;
> + u64 smallest_error = 0;
> + int tries = 0;
> + u64 min_counts = ref * 2000;
> +
> + /* Two subsequent reads with the same offset avoids one off large jitter values */
> + for (int x = 0; x < 10; x++) {
> + ret = cppc_get_perf_ctrs(cpu, fb_ctrs_t0);
> + if (ret)
> + return ret;
> +
> + ret = cppc_get_perf_ctrs(cpu, fb_ctrs_t1);
> + if (ret)
> + return ret;
> +
> + if (last_delivered == cppc_perf_from_fbctrs(ref, fb_ctrs_t0, fb_ctrs_t1))
> + break;
> +
> + last_delivered = cppc_perf_from_fbctrs(ref, fb_ctrs_t0, fb_ctrs_t1);
> + }
Actually I don't quite understand this hunk.
Is it trying to get two exactly same samples of delivered performance?
Isn't that very hard or impossible to meet?
> + last_delivered = 0;
> +again:
> + ndelay(100);
>
> - ret = cppc_get_perf_ctrs(cpu, fb_ctrs_t0);
> + ret = cppc_get_perf_ctrs(cpu, fb_ctrs_t1);
> if (ret)
> return ret;
>
> - udelay(2); /* 2usec delay between sampling */
> + /*
> + * We want at least two significant figures, if the counts are low, then there
> + * can be rounding errors that show up as frequency that is swinging around a few hundred
> + * Mhz. OTOH, if the delay gets too long the clock rate can be affected.
> + * So we want it exactly long enough to have sufficient counter turn over, and
> + * a repeatable low error value.
> + */
> + if ((get_delta(fb_ctrs_t1->reference, fb_ctrs_t0->reference) < min_counts) ||
> + (get_delta(fb_ctrs_t1->delivered, fb_ctrs_t0->delivered) < min_counts)) {
> + s64 delivered = cppc_perf_from_fbctrs(ref, fb_ctrs_t0, fb_ctrs_t1);
> + u64 error = abs(last_delivered - delivered);
> +
> + if (smallest_error == 0 || smallest_error > error)
> + smallest_error = error;
> +
> + if (error > per_cpu(err_floor, cpu)) {
> + last_delivered = delivered;
> + tries++;
> + if (tries < CPPC_SAMPLE_MAX_RETRIES)
> + goto again;
> + }
> + }
>
> - return cppc_get_perf_ctrs(cpu, fb_ctrs_t1);
> + /* compute a running error */
> + per_cpu(err_floor, cpu) = (per_cpu(err_floor, cpu) + smallest_error) / 2;
> +
> + return ret;
Correct me if I'm wrong. The key point is something like a self-adaptation
process to get an appropriate sampling delay for different platforms or
even each CPU?
> }
>
> static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
> @@ -799,7 +851,9 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
>
> cpu_data = policy->driver_data;
>
> - ret = cppc_get_perf_ctrs_sample(cpu, &fb_ctrs_t0, &fb_ctrs_t1);
> + ret = cppc_get_perf_ctrs_sample(cpu, cpu_data->perf_caps.reference_perf,
> + &fb_ctrs_t0, &fb_ctrs_t1);
> +
> if (ret) {
> if (ret == -EFAULT)
> /* Any of the associated CPPC regs is 0. */
^ permalink raw reply
* [GIT PULL] power sequencing fixes for v7.2-rc1
From: Bartosz Golaszewski @ 2026-06-25 8:51 UTC (permalink / raw)
To: Linus Torvalds; +Cc: linux-pm, linux-kernel, brgl, Bartosz Golaszewski
Linus,
Please pull the following set of pwrseq fixes for the upcoming RC.
Thanks,
Bartosz
The following changes since commit 31e6aeafcdde965aa10e10e93ee186520555ec3d:
Merge tag 'pwrseq-updates-for-v7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux (2026-06-16 07:38:04 +0530)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux.git tags/pwrseq-fixes-for-v7.2-rc1
for you to fetch changes up to 2d5a7d406ecece5837af1e278ffbbf6c0315560a:
power: sequencing: fix ABBA deadlock in pwrseq_device_unregister() (2026-06-22 10:05:39 +0200)
----------------------------------------------------------------
power sequencing fixes for v7.2-rc1
- fix an ABBA deadlock in pwrseq unregister path
- fix a use-after-free bug in pwrseq core
- sort PCI device IDs in ascending order in pwrseq-pcie-m2
----------------------------------------------------------------
Bartosz Golaszewski (1):
power: sequencing: fix ABBA deadlock in pwrseq_device_unregister()
Wei Deng (1):
power: sequencing: pcie-m2: Sort PCI device IDs in ascending order
Wentao Liang (1):
pwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next()
drivers/power/sequencing/core.c | 23 +++++++++++++++--------
drivers/power/sequencing/pwrseq-pcie-m2.c | 4 ++--
2 files changed, 17 insertions(+), 10 deletions(-)
^ permalink raw reply
* [PATCH v9 7/7] power: supply: Add charger driver for Asus Transformers
From: Svyatoslav Ryhel @ 2026-06-25 8:15 UTC (permalink / raw)
To: Rob Herring, Krzysztof Kozlowski, Conor Dooley, Dmitry Torokhov,
Lee Jones, Pavel Machek, Sebastian Reichel, Svyatoslav Ryhel,
Ion Agorria, Michał Mirosław
Cc: devicetree, linux-kernel, linux-input, linux-leds, linux-pm
In-Reply-To: <20260625081529.22447-1-clamor95@gmail.com>
From: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Add support for charger detection capabilities found in the embedded
controller of ASUS Transformer devices.
Suggested-by: Maxim Schwalm <maxim.schwalm@gmail.com>
Suggested-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
drivers/power/supply/Kconfig | 11 +
drivers/power/supply/Makefile | 1 +
.../supply/asus-transformer-ec-charger.c | 208 ++++++++++++++++++
3 files changed, 220 insertions(+)
create mode 100644 drivers/power/supply/asus-transformer-ec-charger.c
diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 1dc3d0b2e021..ebc6d5c01330 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -508,6 +508,17 @@ config CHARGER_88PM860X
help
Say Y here to enable charger for Marvell 88PM860x chip.
+config CHARGER_ASUS_TRANSFORMER_EC
+ tristate "Asus Transformer's charger driver"
+ depends on MFD_ASUS_TRANSFORMER_EC
+ help
+ Say Y here to enable support AC plug detection on Asus Transformer
+ Dock.
+
+ This sub-driver supports charger detection mechanism found in Asus
+ Transformer tablets and mobile docks and controlled by special
+ embedded controller.
+
config CHARGER_PF1550
tristate "NXP PF1550 battery charger driver"
depends on MFD_PF1550
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 1313f367715c..93d17d28081e 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_CHARGER_RT9471) += rt9471.o
obj-$(CONFIG_CHARGER_RT9756) += rt9756.o
obj-$(CONFIG_BATTERY_TWL4030_MADC) += twl4030_madc_battery.o
obj-$(CONFIG_CHARGER_88PM860X) += 88pm860x_charger.o
+obj-$(CONFIG_CHARGER_ASUS_TRANSFORMER_EC) += asus-transformer-ec-charger.o
obj-$(CONFIG_CHARGER_PF1550) += pf1550-charger.o
obj-$(CONFIG_BATTERY_RX51) += rx51_battery.o
obj-$(CONFIG_AB8500_BM) += ab8500_bmdata.o ab8500_charger.o ab8500_fg.o ab8500_btemp.o ab8500_chargalg.o
diff --git a/drivers/power/supply/asus-transformer-ec-charger.c b/drivers/power/supply/asus-transformer-ec-charger.c
new file mode 100644
index 000000000000..c7a6bd2ba533
--- /dev/null
+++ b/drivers/power/supply/asus-transformer-ec-charger.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/err.h>
+#include <linux/mfd/asus-transformer-ec.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/property.h>
+
+struct asus_ec_charger_data {
+ struct notifier_block nb;
+ struct asusec_core *ec;
+ struct power_supply *psy;
+ struct power_supply_desc psy_desc;
+};
+
+static enum power_supply_property asus_ec_charger_properties[] = {
+ POWER_SUPPLY_PROP_USB_TYPE,
+ POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR,
+ POWER_SUPPLY_PROP_ONLINE,
+ POWER_SUPPLY_PROP_MODEL_NAME,
+};
+
+static int asus_ec_charger_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct asus_ec_charger_data *priv = power_supply_get_drvdata(psy);
+ enum power_supply_usb_type psu;
+ int ret;
+ u64 ctl;
+
+ /* Check if model name is requested first since it needs no hw access */
+ if (psp == POWER_SUPPLY_PROP_MODEL_NAME) {
+ val->strval = priv->ec->model;
+ return 0;
+ }
+
+ ret = asus_dockram_access_ctl(priv->ec->dockram, &ctl, 0, 0);
+ if (ret)
+ return ret;
+
+ switch (ctl & (ASUSEC_CTL_FULL_POWER_SOURCE | ASUSEC_CTL_DIRECT_POWER_SOURCE)) {
+ case ASUSEC_CTL_FULL_POWER_SOURCE:
+ psu = POWER_SUPPLY_USB_TYPE_CDP; /* DOCK */
+ break;
+ case ASUSEC_CTL_DIRECT_POWER_SOURCE:
+ psu = POWER_SUPPLY_USB_TYPE_SDP; /* USB */
+ break;
+ case 0:
+ psu = POWER_SUPPLY_USB_TYPE_UNKNOWN; /* no power source connected */
+ break;
+ default:
+ psu = POWER_SUPPLY_USB_TYPE_ACA; /* power adapter */
+ break;
+ }
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_ONLINE:
+ val->intval = psu != POWER_SUPPLY_USB_TYPE_UNKNOWN;
+ return 0;
+
+ case POWER_SUPPLY_PROP_USB_TYPE:
+ val->intval = psu;
+ return 0;
+
+ case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
+ if (ctl & ASUSEC_CTL_TEST_DISCHARGE)
+ val->intval = POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE;
+ else if (ctl & ASUSEC_CTL_USB_CHARGE)
+ val->intval = POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO;
+ else
+ val->intval = POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE;
+ return 0;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int asus_ec_charger_set_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ const union power_supply_propval *val)
+{
+ struct asus_ec_charger_data *priv = power_supply_get_drvdata(psy);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
+ switch ((enum power_supply_charge_behaviour)val->intval) {
+ case POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO:
+ return asus_dockram_access_ctl(priv->ec->dockram, NULL,
+ ASUSEC_CTL_TEST_DISCHARGE | ASUSEC_CTL_USB_CHARGE,
+ ASUSEC_CTL_USB_CHARGE);
+
+ case POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE:
+ return asus_dockram_access_ctl(priv->ec->dockram, NULL,
+ ASUSEC_CTL_TEST_DISCHARGE | ASUSEC_CTL_USB_CHARGE, 0);
+
+ case POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE:
+ return asus_dockram_access_ctl(priv->ec->dockram, NULL,
+ ASUSEC_CTL_TEST_DISCHARGE | ASUSEC_CTL_USB_CHARGE,
+ ASUSEC_CTL_TEST_DISCHARGE);
+ default:
+ return -EINVAL;
+ }
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int asus_ec_charger_property_is_writeable(struct power_supply *psy,
+ enum power_supply_property psp)
+{
+ switch (psp) {
+ case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static const struct power_supply_desc asus_ec_charger_desc = {
+ .name = "asus-ec-charger",
+ .type = POWER_SUPPLY_TYPE_USB,
+ .charge_behaviours = BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO) |
+ BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE) |
+ BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE),
+ .usb_types = BIT(POWER_SUPPLY_USB_TYPE_UNKNOWN) |
+ BIT(POWER_SUPPLY_USB_TYPE_SDP) |
+ BIT(POWER_SUPPLY_USB_TYPE_CDP) |
+ BIT(POWER_SUPPLY_USB_TYPE_ACA),
+ .properties = asus_ec_charger_properties,
+ .num_properties = ARRAY_SIZE(asus_ec_charger_properties),
+ .get_property = asus_ec_charger_get_property,
+ .set_property = asus_ec_charger_set_property,
+ .property_is_writeable = asus_ec_charger_property_is_writeable,
+ .no_thermal = true,
+};
+
+static int asus_ec_charger_notify(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct asus_ec_charger_data *priv =
+ container_of(nb, struct asus_ec_charger_data, nb);
+
+ switch (action) {
+ case ASUSEC_SMI_ACTION(POWER_NOTIFY):
+ case ASUSEC_SMI_ACTION(ADAPTER_EVENT):
+ power_supply_changed(priv->psy);
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static int asus_ec_charger_probe(struct platform_device *pdev)
+{
+ struct asusec_core *ec = dev_get_drvdata(pdev->dev.parent);
+ struct asus_ec_charger_data *priv;
+ struct device *dev = &pdev->dev;
+ struct power_supply_config cfg = { };
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, priv);
+ priv->ec = ec;
+
+ cfg.fwnode = dev_fwnode(dev->parent);
+ cfg.drv_data = priv;
+
+ memcpy(&priv->psy_desc, &asus_ec_charger_desc, sizeof(priv->psy_desc));
+ priv->psy_desc.name = devm_kasprintf(dev, GFP_KERNEL, "%s-charger",
+ priv->ec->name);
+ if (!priv->psy_desc.name)
+ return -ENOMEM;
+
+ priv->psy = devm_power_supply_register(dev, &priv->psy_desc, &cfg);
+ if (IS_ERR(priv->psy))
+ return dev_err_probe(dev, PTR_ERR(priv->psy),
+ "Failed to register power supply\n");
+
+ priv->nb.notifier_call = asus_ec_charger_notify;
+
+ return blocking_notifier_chain_register(&ec->notify_list, &priv->nb);
+}
+
+static void asus_ec_charger_remove(struct platform_device *pdev)
+{
+ struct asus_ec_charger_data *priv = platform_get_drvdata(pdev);
+ struct asusec_core *ec = priv->ec;
+
+ blocking_notifier_chain_unregister(&ec->notify_list, &priv->nb);
+}
+
+static struct platform_driver asus_ec_charger_driver = {
+ .driver.name = "asus-transformer-ec-charger",
+ .probe = asus_ec_charger_probe,
+ .remove = asus_ec_charger_remove,
+};
+module_platform_driver(asus_ec_charger_driver);
+
+MODULE_ALIAS("platform:asus-transformer-ec-charger");
+MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
+MODULE_DESCRIPTION("ASUS Transformer Pad battery charger driver");
+MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related
* [PATCH v9 6/7] power: supply: Add driver for ASUS Transformer battery
From: Svyatoslav Ryhel @ 2026-06-25 8:15 UTC (permalink / raw)
To: Rob Herring, Krzysztof Kozlowski, Conor Dooley, Dmitry Torokhov,
Lee Jones, Pavel Machek, Sebastian Reichel, Svyatoslav Ryhel,
Ion Agorria, Michał Mirosław
Cc: devicetree, linux-kernel, linux-input, linux-leds, linux-pm
In-Reply-To: <20260625081529.22447-1-clamor95@gmail.com>
From: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Driver implements one battery cell per EC controller and supports reading
of battery status for ASUS Transformer's pad and mobile dock.
Co-developed-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
drivers/power/supply/Kconfig | 11 +
drivers/power/supply/Makefile | 1 +
.../supply/asus-transformer-ec-battery.c | 289 ++++++++++++++++++
3 files changed, 301 insertions(+)
create mode 100644 drivers/power/supply/asus-transformer-ec-battery.c
diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 83392ed6a8da..1dc3d0b2e021 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -122,6 +122,17 @@ config BATTERY_CHAGALL
This driver can also be built as a module. If so, the module will be
called chagall-battery.
+config BATTERY_ASUS_TRANSFORMER_EC
+ tristate "Asus Transformer's battery driver"
+ depends on MFD_ASUS_TRANSFORMER_EC
+ help
+ Say Y to enable support for battery status access on Tegra based
+ ASUS Transformer devices.
+
+ This sub-driver supports battery cells found in Asus Transformer
+ tablets and mobile docks and controlled by a special embedded
+ controller.
+
config BATTERY_CPCAP
tristate "Motorola CPCAP PMIC battery driver"
depends on MFD_CPCAP && IIO
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 7ee839dca7f3..1313f367715c 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_TEST_POWER) += test_power.o
obj-$(CONFIG_BATTERY_88PM860X) += 88pm860x_battery.o
obj-$(CONFIG_CHARGER_ADP5061) += adp5061.o
obj-$(CONFIG_BATTERY_ACT8945A) += act8945a_charger.o
+obj-$(CONFIG_BATTERY_ASUS_TRANSFORMER_EC) += asus-transformer-ec-battery.o
obj-$(CONFIG_BATTERY_AXP20X) += axp20x_battery.o
obj-$(CONFIG_CHARGER_AXP20X) += axp20x_ac_power.o
obj-$(CONFIG_BATTERY_CHAGALL) += chagall-battery.o
diff --git a/drivers/power/supply/asus-transformer-ec-battery.c b/drivers/power/supply/asus-transformer-ec-battery.c
new file mode 100644
index 000000000000..4c0c6d4b09e2
--- /dev/null
+++ b/drivers/power/supply/asus-transformer-ec-battery.c
@@ -0,0 +1,289 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/array_size.h>
+#include <linux/devm-helpers.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mfd/asus-transformer-ec.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/property.h>
+#include <linux/unaligned.h>
+
+#define ASUSEC_BATTERY_DATA_FRESH_MSEC 5000
+
+#define ASUSEC_BATTERY_DISCHARGING BIT(6)
+#define ASUSEC_BATTERY_FULL_CHARGED BIT(5)
+#define ASUSEC_BATTERY_NOT_CHARGING BIT(4)
+
+#define TEMP_CELSIUS_OFFSET 2731
+
+struct asus_ec_battery_data {
+ struct asusec_core *ec;
+ struct power_supply *battery;
+ struct power_supply_desc psy_desc;
+ struct delayed_work poll_work;
+ struct mutex battery_lock; /* for data refresh */
+ unsigned long batt_data_ts;
+ int last_state;
+ u8 batt_data[ASUSEC_ENTRY_BUFSIZE];
+};
+
+static int asus_ec_battery_refresh(struct asus_ec_battery_data *priv)
+{
+ struct i2c_client *client = priv->ec->dockram;
+ struct device *dev = &client->dev;
+ int ret = 0;
+
+ if (time_before(jiffies, priv->batt_data_ts))
+ return ret;
+
+ memset(priv->batt_data, 0, ASUSEC_ENTRY_BUFSIZE);
+ ret = i2c_smbus_read_i2c_block_data(client, ASUSEC_DOCKRAM_BATT_CTL,
+ ASUSEC_ENTRY_SIZE, priv->batt_data);
+ if (ret < ASUSEC_ENTRY_SIZE)
+ return ret < 0 ? ret : -EIO;
+
+ if (priv->batt_data[0] > ASUSEC_ENTRY_SIZE) {
+ dev_err(dev, "bad data len; buffer: %*ph; ret: %d\n",
+ ASUSEC_ENTRY_BUFSIZE, priv->batt_data, ret);
+ return -EPROTO;
+ }
+
+ priv->batt_data_ts = jiffies +
+ msecs_to_jiffies(ASUSEC_BATTERY_DATA_FRESH_MSEC);
+
+ return ret;
+}
+
+static enum power_supply_property asus_ec_battery_properties[] = {
+ POWER_SUPPLY_PROP_STATUS,
+ POWER_SUPPLY_PROP_VOLTAGE_MAX,
+ POWER_SUPPLY_PROP_CURRENT_MAX,
+ POWER_SUPPLY_PROP_TEMP,
+ POWER_SUPPLY_PROP_VOLTAGE_NOW,
+ POWER_SUPPLY_PROP_CURRENT_NOW,
+ POWER_SUPPLY_PROP_CAPACITY,
+ POWER_SUPPLY_PROP_CHARGE_NOW,
+ POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
+ POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
+ POWER_SUPPLY_PROP_PRESENT,
+};
+
+static const unsigned int asus_ec_battery_prop_offs[] = {
+ [POWER_SUPPLY_PROP_STATUS] = 1,
+ [POWER_SUPPLY_PROP_VOLTAGE_MAX] = 3,
+ [POWER_SUPPLY_PROP_CURRENT_MAX] = 5,
+ [POWER_SUPPLY_PROP_TEMP] = 7,
+ [POWER_SUPPLY_PROP_VOLTAGE_NOW] = 9,
+ [POWER_SUPPLY_PROP_CURRENT_NOW] = 11,
+ [POWER_SUPPLY_PROP_CAPACITY] = 13,
+ [POWER_SUPPLY_PROP_CHARGE_NOW] = 15,
+ [POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW] = 17,
+ [POWER_SUPPLY_PROP_TIME_TO_FULL_NOW] = 19,
+};
+
+static int asus_ec_battery_get_value(struct asus_ec_battery_data *priv,
+ enum power_supply_property psp)
+{
+ int ret, offs;
+
+ guard(mutex)(&priv->battery_lock);
+
+ if (psp >= ARRAY_SIZE(asus_ec_battery_prop_offs))
+ return -EINVAL;
+
+ offs = asus_ec_battery_prop_offs[psp];
+ if (!offs)
+ return -EINVAL;
+
+ ret = asus_ec_battery_refresh(priv);
+ if (ret < 0)
+ return ret;
+
+ if (offs >= priv->batt_data[0])
+ return -ENODATA;
+
+ return get_unaligned_le16(priv->batt_data + offs);
+}
+
+static int asus_ec_battery_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct asus_ec_battery_data *priv = power_supply_get_drvdata(psy);
+ int ret;
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_PRESENT:
+ val->intval = 1;
+ break;
+
+ default:
+ ret = asus_ec_battery_get_value(priv, psp);
+ if (ret < 0)
+ return ret;
+
+ val->intval = (s16)ret;
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_STATUS:
+ if (ret & ASUSEC_BATTERY_FULL_CHARGED)
+ val->intval = POWER_SUPPLY_STATUS_FULL;
+ else if (ret & ASUSEC_BATTERY_NOT_CHARGING)
+ val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+ else if (ret & ASUSEC_BATTERY_DISCHARGING)
+ val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+ else
+ val->intval = POWER_SUPPLY_STATUS_CHARGING;
+ break;
+
+ case POWER_SUPPLY_PROP_TEMP:
+ val->intval -= TEMP_CELSIUS_OFFSET;
+ break;
+
+ case POWER_SUPPLY_PROP_CHARGE_NOW:
+ case POWER_SUPPLY_PROP_CURRENT_NOW:
+ case POWER_SUPPLY_PROP_CURRENT_MAX:
+ case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+ case POWER_SUPPLY_PROP_VOLTAGE_MAX:
+ val->intval *= 1000;
+ break;
+
+ case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
+ case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
+ val->intval *= 60;
+ break;
+
+ default:
+ break;
+ }
+
+ break;
+ }
+
+ return 0;
+}
+
+static void asus_ec_battery_poll_work(struct work_struct *work)
+{
+ struct asus_ec_battery_data *priv =
+ container_of(work, struct asus_ec_battery_data, poll_work.work);
+ int state;
+
+ state = asus_ec_battery_get_value(priv, POWER_SUPPLY_PROP_STATUS);
+ if (state < 0)
+ goto reschedule;
+
+ if (state & ASUSEC_BATTERY_FULL_CHARGED)
+ state = POWER_SUPPLY_STATUS_FULL;
+ else if (state & ASUSEC_BATTERY_NOT_CHARGING)
+ state = POWER_SUPPLY_STATUS_NOT_CHARGING;
+ else if (state & ASUSEC_BATTERY_DISCHARGING)
+ state = POWER_SUPPLY_STATUS_DISCHARGING;
+ else
+ state = POWER_SUPPLY_STATUS_CHARGING;
+
+ if (priv->last_state != state) {
+ priv->last_state = state;
+ power_supply_changed(priv->battery);
+ }
+
+reschedule:
+ /* continuously send uevent notification */
+ schedule_delayed_work(&priv->poll_work,
+ msecs_to_jiffies(ASUSEC_BATTERY_DATA_FRESH_MSEC));
+}
+
+static const struct power_supply_desc asus_ec_battery_desc = {
+ .name = "asus-ec-battery",
+ .type = POWER_SUPPLY_TYPE_BATTERY,
+ .properties = asus_ec_battery_properties,
+ .num_properties = ARRAY_SIZE(asus_ec_battery_properties),
+ .get_property = asus_ec_battery_get_property,
+ .external_power_changed = power_supply_changed,
+};
+
+static int asus_ec_battery_probe(struct platform_device *pdev)
+{
+ struct asusec_core *ec = dev_get_drvdata(pdev->dev.parent);
+ struct asus_ec_battery_data *priv;
+ struct device *dev = &pdev->dev;
+ struct power_supply_config cfg = { };
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, priv);
+
+ mutex_init(&priv->battery_lock);
+
+ priv->ec = ec;
+ priv->batt_data_ts = jiffies - 1;
+ priv->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
+
+ cfg.fwnode = dev_fwnode(dev->parent);
+ cfg.drv_data = priv;
+
+ memcpy(&priv->psy_desc, &asus_ec_battery_desc, sizeof(priv->psy_desc));
+ priv->psy_desc.name = devm_kasprintf(dev, GFP_KERNEL, "%s-battery",
+ priv->ec->name);
+ if (!priv->psy_desc.name)
+ return -ENOMEM;
+
+ priv->battery = devm_power_supply_register(dev, &priv->psy_desc, &cfg);
+ if (IS_ERR(priv->battery))
+ return dev_err_probe(dev, PTR_ERR(priv->battery),
+ "Failed to register power supply\n");
+
+ ret = devm_delayed_work_autocancel(dev, &priv->poll_work,
+ asus_ec_battery_poll_work);
+ if (ret)
+ return ret;
+
+ schedule_delayed_work(&priv->poll_work,
+ msecs_to_jiffies(ASUSEC_BATTERY_DATA_FRESH_MSEC));
+
+ return 0;
+}
+
+static int __maybe_unused asus_ec_battery_suspend(struct device *dev)
+{
+ struct asus_ec_battery_data *priv = dev_get_drvdata(dev);
+
+ cancel_delayed_work_sync(&priv->poll_work);
+
+ return 0;
+}
+
+static int __maybe_unused asus_ec_battery_resume(struct device *dev)
+{
+ struct asus_ec_battery_data *priv = dev_get_drvdata(dev);
+
+ schedule_delayed_work(&priv->poll_work,
+ msecs_to_jiffies(ASUSEC_BATTERY_DATA_FRESH_MSEC));
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(asus_ec_battery_pm_ops,
+ asus_ec_battery_suspend, asus_ec_battery_resume);
+
+static struct platform_driver asus_ec_battery_driver = {
+ .driver = {
+ .name = "asus-transformer-ec-battery",
+ .pm = &asus_ec_battery_pm_ops,
+ },
+ .probe = asus_ec_battery_probe,
+};
+module_platform_driver(asus_ec_battery_driver);
+
+MODULE_ALIAS("platform:asus-transformer-ec-battery");
+MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
+MODULE_AUTHOR("Svyatoslav Ryhel <clamor95@gmail.com>");
+MODULE_DESCRIPTION("ASUS Transformer's battery driver");
+MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related
* [PATCH v9 5/7] leds: Add driver for ASUS Transformer LEDs
From: Svyatoslav Ryhel @ 2026-06-25 8:15 UTC (permalink / raw)
To: Rob Herring, Krzysztof Kozlowski, Conor Dooley, Dmitry Torokhov,
Lee Jones, Pavel Machek, Sebastian Reichel, Svyatoslav Ryhel,
Ion Agorria, Michał Mirosław
Cc: devicetree, linux-kernel, linux-input, linux-leds, linux-pm
In-Reply-To: <20260625081529.22447-1-clamor95@gmail.com>
From: Michał Mirosław <mirq-linux@rere.qmqm.pl>
ASUS Transformer tablets have a green and an amber LED on both the Pad
and the Dock. If both LEDs are enabled simultaneously, the emitted light
will be yellow.
Co-developed-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
---
drivers/leds/Kconfig | 11 +++
drivers/leds/Makefile | 1 +
drivers/leds/leds-asus-transformer-ec.c | 125 ++++++++++++++++++++++++
3 files changed, 137 insertions(+)
create mode 100644 drivers/leds/leds-asus-transformer-ec.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index f4a0a3c8c870..f637d23400a8 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -120,6 +120,17 @@ config LEDS_OSRAM_AMS_AS3668
To compile this driver as a module, choose M here: the module
will be called leds-as3668.
+config LEDS_ASUS_TRANSFORMER_EC
+ tristate "LED Support for Asus Transformer charging LED"
+ depends on LEDS_CLASS
+ depends on MFD_ASUS_TRANSFORMER_EC
+ help
+ This option enables support for charging indicator on
+ Asus Transformer's Pad and it's Dock.
+
+ To compile this driver as a module, choose M here: the module
+ will be called leds-asus-transformer-ec.
+
config LEDS_AW200XX
tristate "LED support for Awinic AW20036/AW20054/AW20072/AW20108"
depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 8fdb45d5b439..d5395c3f1124 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_LEDS_AN30259A) += leds-an30259a.o
obj-$(CONFIG_LEDS_APU) += leds-apu.o
obj-$(CONFIG_LEDS_ARIEL) += leds-ariel.o
obj-$(CONFIG_LEDS_AS3668) += leds-as3668.o
+obj-$(CONFIG_LEDS_ASUS_TRANSFORMER_EC) += leds-asus-transformer-ec.o
obj-$(CONFIG_LEDS_AW200XX) += leds-aw200xx.o
obj-$(CONFIG_LEDS_AW2013) += leds-aw2013.o
obj-$(CONFIG_LEDS_BCM6328) += leds-bcm6328.o
diff --git a/drivers/leds/leds-asus-transformer-ec.c b/drivers/leds/leds-asus-transformer-ec.c
new file mode 100644
index 000000000000..4421d629911e
--- /dev/null
+++ b/drivers/leds/leds-asus-transformer-ec.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/err.h>
+#include <linux/leds.h>
+#include <linux/mfd/asus-transformer-ec.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+enum {
+ ASUSEC_LED_AMBER,
+ ASUSEC_LED_GREEN,
+ ASUSEC_LED_MAX
+};
+
+struct asus_ec_led_config {
+ const char *name;
+ unsigned int color;
+ u64 ctrl_bit;
+};
+
+struct asus_ec_led {
+ struct asus_ec_leds_data *ddata;
+ struct led_classdev cdev;
+ u64 ctrl_bit;
+};
+
+struct asus_ec_leds_data {
+ const struct asusec_core *ec;
+ struct asus_ec_led leds[ASUSEC_LED_MAX];
+};
+
+static const struct asus_ec_led_config asus_ec_leds[] = {
+ [ASUSEC_LED_AMBER] = {
+ .name = "amber",
+ .color = LED_COLOR_ID_AMBER,
+ .ctrl_bit = ASUSEC_CTL_LED_AMBER,
+ },
+ [ASUSEC_LED_GREEN] = {
+ .name = "green",
+ .color = LED_COLOR_ID_GREEN,
+ .ctrl_bit = ASUSEC_CTL_LED_GREEN,
+ },
+};
+
+static enum led_brightness asus_ec_led_get_brightness(struct led_classdev *cdev)
+{
+ struct asus_ec_led *led = container_of(cdev, struct asus_ec_led, cdev);
+ const struct asusec_core *ec = led->ddata->ec;
+ u64 ctl;
+ int ret;
+
+ ret = asus_dockram_access_ctl(ec->dockram, &ctl, 0, 0);
+ if (ret)
+ return LED_OFF;
+
+ return ctl & led->ctrl_bit ? LED_ON : LED_OFF;
+}
+
+static int asus_ec_led_set_brightness(struct led_classdev *cdev,
+ enum led_brightness brightness)
+{
+ struct asus_ec_led *led = container_of(cdev, struct asus_ec_led, cdev);
+ const struct asusec_core *ec = led->ddata->ec;
+
+ if (brightness)
+ return asus_dockram_access_ctl(ec->dockram, NULL,
+ led->ctrl_bit, led->ctrl_bit);
+
+ return asus_dockram_access_ctl(ec->dockram, NULL, led->ctrl_bit, 0);
+}
+
+static int asus_ec_led_probe(struct platform_device *pdev)
+{
+ const struct asusec_core *ec = dev_get_drvdata(pdev->dev.parent);
+ struct asus_ec_leds_data *ddata;
+ struct device *dev = &pdev->dev;
+ int ret;
+
+ ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
+ if (!ddata)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, ddata);
+ ddata->ec = ec;
+
+ for (int i = 0; i < ASUSEC_LED_MAX; i++) {
+ const struct asus_ec_led_config *cfg = &asus_ec_leds[i];
+ struct asus_ec_led *led = &ddata->leds[i];
+
+ led->cdev.name = devm_kasprintf(dev, GFP_KERNEL, "%s::%s",
+ ddata->ec->name, cfg->name);
+ if (!led->cdev.name)
+ return -ENOMEM;
+
+ led->cdev.max_brightness = 1;
+ led->cdev.color = cfg->color;
+ led->cdev.flags = LED_CORE_SUSPENDRESUME | LED_RETAIN_AT_SHUTDOWN;
+ led->cdev.brightness_get = asus_ec_led_get_brightness;
+ led->cdev.brightness_set_blocking = asus_ec_led_set_brightness;
+
+ led->ddata = ddata;
+ led->ctrl_bit = cfg->ctrl_bit;
+
+ ret = devm_led_classdev_register(dev, &led->cdev);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to register %s LED\n",
+ cfg->name);
+ }
+
+ return 0;
+}
+
+static struct platform_driver asus_ec_led_driver = {
+ .driver.name = "asus-transformer-ec-led",
+ .probe = asus_ec_led_probe,
+};
+module_platform_driver(asus_ec_led_driver);
+
+MODULE_ALIAS("platform:asus-transformer-ec-led");
+MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
+MODULE_AUTHOR("Svyatoslav Ryhel <clamor95@gmail.com>");
+MODULE_DESCRIPTION("ASUS Transformer's charging LED driver");
+MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related
* [PATCH v9 4/7] input: keyboard: Add driver for ASUS Transformer dock multimedia keys
From: Svyatoslav Ryhel @ 2026-06-25 8:15 UTC (permalink / raw)
To: Rob Herring, Krzysztof Kozlowski, Conor Dooley, Dmitry Torokhov,
Lee Jones, Pavel Machek, Sebastian Reichel, Svyatoslav Ryhel,
Ion Agorria, Michał Mirosław
Cc: devicetree, linux-kernel, linux-input, linux-leds, linux-pm
In-Reply-To: <20260625081529.22447-1-clamor95@gmail.com>
From: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Add support for multimedia top button row of ASUS Transformer's Mobile
Dock keyboard. Driver is made that function keys (F1-F12) are used by
default which suits average Linux use better and with pressing
ScreenLock + AltGr function keys layout is switched to multimedia keys.
Only Dock keyboard input events are tracked for AltGr pressing.
Co-developed-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
---
drivers/input/keyboard/Kconfig | 10 +
drivers/input/keyboard/Makefile | 1 +
.../input/keyboard/asus-transformer-ec-keys.c | 314 ++++++++++++++++++
3 files changed, 325 insertions(+)
create mode 100644 drivers/input/keyboard/asus-transformer-ec-keys.c
diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 9d1019ba0245..913cb4900565 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -89,6 +89,16 @@ config KEYBOARD_APPLESPI
To compile this driver as a module, choose M here: the
module will be called applespi.
+config KEYBOARD_ASUS_TRANSFORMER_EC
+ tristate "Asus Transformer's Mobile Dock multimedia keys"
+ depends on MFD_ASUS_TRANSFORMER_EC
+ help
+ Say Y here if you want to use multimedia keys present on Asus
+ Transformer's Mobile Dock.
+
+ To compile this driver as a module, choose M here: the
+ module will be called asus-transformer-ec-keys.
+
config KEYBOARD_ATARI
tristate "Atari keyboard"
depends on ATARI
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 60bb7baf802f..0d81096887ad 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_KEYBOARD_ADP5585) += adp5585-keys.o
obj-$(CONFIG_KEYBOARD_ADP5588) += adp5588-keys.o
obj-$(CONFIG_KEYBOARD_AMIGA) += amikbd.o
obj-$(CONFIG_KEYBOARD_APPLESPI) += applespi.o
+obj-$(CONFIG_KEYBOARD_ASUS_TRANSFORMER_EC) += asus-transformer-ec-keys.o
obj-$(CONFIG_KEYBOARD_ATARI) += atakbd.o
obj-$(CONFIG_KEYBOARD_ATKBD) += atkbd.o
obj-$(CONFIG_KEYBOARD_BCM) += bcm-keypad.o
diff --git a/drivers/input/keyboard/asus-transformer-ec-keys.c b/drivers/input/keyboard/asus-transformer-ec-keys.c
new file mode 100644
index 000000000000..53aff3ce7146
--- /dev/null
+++ b/drivers/input/keyboard/asus-transformer-ec-keys.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/array_size.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/mfd/asus-transformer-ec.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define ASUSEC_EXT_KEY_CODES 0x20
+
+struct asus_ec_keys_data {
+ struct notifier_block nb;
+ struct asusec_core *ec;
+ struct input_dev *xidev;
+ struct input_handler input_handler;
+ unsigned short keymap[ASUSEC_EXT_KEY_CODES * 2];
+ const char *kbc_phys;
+ bool special_key_pressed;
+ bool special_key_mode;
+};
+
+static void asus_ec_input_event(struct input_handle *handle,
+ unsigned int event_type,
+ unsigned int event_code, int value)
+{
+ struct asus_ec_keys_data *priv = handle->handler->private;
+
+ /* Store special key state */
+ if (event_type == EV_KEY && event_code == KEY_RIGHTALT)
+ priv->special_key_pressed = !!value;
+}
+
+static int asus_ec_input_connect(struct input_handler *handler,
+ struct input_dev *dev,
+ const struct input_device_id *id)
+{
+ struct asus_ec_keys_data *priv = handler->private;
+ struct input_handle *handle;
+ int error;
+
+ if (!dev->phys || !strstr(dev->phys, priv->kbc_phys))
+ return -ENODEV;
+
+ handle = kzalloc_obj(*handle);
+ if (!handle)
+ return -ENOMEM;
+
+ handle->dev = dev;
+ handle->handler = handler;
+ handle->name = handler->name;
+
+ error = input_register_handle(handle);
+ if (error)
+ goto err_free_handle;
+
+ error = input_open_device(handle);
+ if (error)
+ goto err_unregister_handle;
+
+ return 0;
+
+ err_unregister_handle:
+ input_unregister_handle(handle);
+ err_free_handle:
+ kfree(handle);
+
+ return error;
+}
+
+static void asus_ec_input_disconnect(struct input_handle *handle)
+{
+ input_close_device(handle);
+ input_unregister_handle(handle);
+ kfree(handle);
+}
+
+static const struct input_device_id asus_ec_input_ids[] = {
+ {
+ .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
+ .evbit = { BIT_MASK(EV_KEY) },
+ },
+ { }
+};
+
+static const unsigned short asus_ec_dock_ext_keys[] = {
+ /* Function keys [0x00 - 0x19] */
+ [0x01] = KEY_DELETE,
+ [0x02] = KEY_F1,
+ [0x03] = KEY_F2,
+ [0x04] = KEY_F3,
+ [0x05] = KEY_F4,
+ [0x06] = KEY_F5,
+ [0x07] = KEY_F6,
+ [0x08] = KEY_F7,
+ [0x10] = KEY_F8,
+ [0x11] = KEY_F9,
+ [0x12] = KEY_F10,
+ [0x13] = KEY_F11,
+ [0x14] = KEY_F12,
+ [0x15] = KEY_MUTE,
+ [0x16] = KEY_VOLUMEDOWN,
+ [0x17] = KEY_VOLUMEUP,
+ /* Multimedia keys [0x20 - 0x39] */
+ [0x21] = KEY_SCREENLOCK,
+ [0x22] = KEY_WLAN,
+ [0x23] = KEY_BLUETOOTH,
+ [0x24] = KEY_TOUCHPAD_TOGGLE,
+ [0x25] = KEY_BRIGHTNESSDOWN,
+ [0x26] = KEY_BRIGHTNESSUP,
+ [0x27] = KEY_BRIGHTNESS_AUTO,
+ [0x28] = KEY_PRINT,
+ [0x30] = KEY_WWW,
+ [0x31] = KEY_CONFIG,
+ [0x32] = KEY_PREVIOUSSONG,
+ [0x33] = KEY_PLAYPAUSE,
+ [0x34] = KEY_NEXTSONG,
+ [0x35] = KEY_MUTE,
+ [0x36] = KEY_VOLUMEDOWN,
+ [0x37] = KEY_VOLUMEUP,
+};
+
+static void asus_ec_keys_report_key(struct input_dev *dev, unsigned int code,
+ unsigned int key, bool value)
+{
+ input_event(dev, EV_MSC, MSC_SCAN, code);
+ input_report_key(dev, key, value);
+ input_sync(dev);
+}
+
+static int asus_ec_keys_process_key(struct input_dev *dev, u8 code)
+{
+ struct asus_ec_keys_data *priv = dev_get_drvdata(dev->dev.parent);
+ unsigned int key = 0;
+
+ if (code == 0)
+ return NOTIFY_DONE;
+
+ /* Flip special key mode state when pressing SCREEN LOCK + R ALT */
+ if (priv->special_key_pressed && code == 1) {
+ priv->special_key_mode = !priv->special_key_mode;
+ return NOTIFY_DONE;
+ }
+
+ /*
+ * Relocate code to second "page" if pressed state XOR's mode state
+ * This way special key will invert the current mode
+ */
+ if (priv->special_key_mode ^ priv->special_key_pressed)
+ code += ASUSEC_EXT_KEY_CODES;
+
+ if (code < dev->keycodemax) {
+ unsigned short *map = dev->keycode;
+
+ key = map[code];
+ }
+
+ if (!key)
+ key = KEY_UNKNOWN;
+
+ asus_ec_keys_report_key(dev, code, key, 1);
+ asus_ec_keys_report_key(dev, code, key, 0);
+
+ return NOTIFY_OK;
+}
+
+static int asus_ec_keys_notify(struct notifier_block *nb,
+ unsigned long action, void *data_)
+{
+ struct asus_ec_keys_data *priv =
+ container_of(nb, struct asus_ec_keys_data, nb);
+ u8 *data = data_;
+
+ if (action & ASUSEC_SMI_MASK)
+ return NOTIFY_DONE;
+
+ if (action & ASUSEC_SCI_MASK)
+ return asus_ec_keys_process_key(priv->xidev, data[2]);
+
+ return NOTIFY_DONE;
+}
+
+static void asus_ec_keys_setup_keymap(struct asus_ec_keys_data *priv)
+{
+ struct input_dev *dev = priv->xidev;
+ unsigned int i;
+
+ BUILD_BUG_ON(ARRAY_SIZE(priv->keymap) < ARRAY_SIZE(asus_ec_dock_ext_keys));
+
+ dev->keycode = priv->keymap;
+ dev->keycodesize = sizeof(*priv->keymap);
+ dev->keycodemax = ARRAY_SIZE(priv->keymap);
+
+ input_set_capability(dev, EV_MSC, MSC_SCAN);
+ input_set_capability(dev, EV_KEY, KEY_UNKNOWN);
+
+ for (i = 0; i < ARRAY_SIZE(asus_ec_dock_ext_keys); i++) {
+ unsigned int code = asus_ec_dock_ext_keys[i];
+
+ if (!code)
+ continue;
+
+ __set_bit(code, dev->keybit);
+ priv->keymap[i] = code;
+ }
+}
+
+static int asus_ec_keys_register_handler(struct device *dev,
+ struct asus_ec_keys_data *priv)
+{
+ struct i2c_client *parent = to_i2c_client(dev->parent);
+ int error;
+
+ priv->input_handler.event = asus_ec_input_event;
+ priv->input_handler.connect = asus_ec_input_connect;
+ priv->input_handler.disconnect = asus_ec_input_disconnect;
+ priv->input_handler.id_table = asus_ec_input_ids;
+ priv->input_handler.passive_observer = true;
+ priv->input_handler.private = priv;
+ priv->input_handler.name = devm_kasprintf(dev, GFP_KERNEL,
+ "%s-media-handler",
+ priv->ec->name);
+ if (!priv->input_handler.name)
+ return -ENOMEM;
+
+ priv->kbc_phys = devm_kasprintf(dev, GFP_KERNEL, "i2c-%u-%04x/serio0",
+ i2c_adapter_id(parent->adapter),
+ parent->addr);
+ if (!priv->kbc_phys)
+ return -ENOMEM;
+
+ error = input_register_handler(&priv->input_handler);
+ if (error)
+ return error;
+
+ return 0;
+}
+
+static int asus_ec_keys_probe(struct platform_device *pdev)
+{
+ struct i2c_client *parent = to_i2c_client(pdev->dev.parent);
+ struct asusec_core *ec = dev_get_drvdata(pdev->dev.parent);
+ struct device *dev = &pdev->dev;
+ struct asus_ec_keys_data *priv;
+ int error;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, priv);
+ priv->ec = ec;
+
+ priv->xidev = devm_input_allocate_device(dev);
+ if (!priv->xidev)
+ return -ENOMEM;
+
+ priv->xidev->name = devm_kasprintf(dev, GFP_KERNEL, "%s Keyboard Ext",
+ ec->model);
+ priv->xidev->phys = devm_kasprintf(dev, GFP_KERNEL, "i2c-%u-%04x",
+ i2c_adapter_id(parent->adapter),
+ parent->addr);
+
+ if (!priv->xidev->name || !priv->xidev->phys)
+ return -ENOMEM;
+
+ asus_ec_keys_setup_keymap(priv);
+
+ error = input_register_device(priv->xidev);
+ if (error)
+ return dev_err_probe(dev, error,
+ "failed to register extension keys\n");
+
+ error = asus_ec_keys_register_handler(dev, priv);
+ if (error) {
+ input_unregister_device(priv->xidev);
+ return error;
+ }
+
+ priv->nb.notifier_call = asus_ec_keys_notify;
+
+ error = blocking_notifier_chain_register(&ec->notify_list, &priv->nb);
+ if (error) {
+ input_unregister_device(priv->xidev);
+ input_unregister_handler(&priv->input_handler);
+ return error;
+ }
+
+ return 0;
+}
+
+static void asus_ec_keys_remove(struct platform_device *pdev)
+{
+ struct asus_ec_keys_data *priv = platform_get_drvdata(pdev);
+ struct asusec_core *ec = priv->ec;
+
+ blocking_notifier_chain_unregister(&ec->notify_list, &priv->nb);
+ input_unregister_handler(&priv->input_handler);
+ input_unregister_device(priv->xidev);
+}
+
+static struct platform_driver asus_ec_keys_driver = {
+ .driver.name = "asus-transformer-ec-keys",
+ .probe = asus_ec_keys_probe,
+ .remove = asus_ec_keys_remove,
+};
+module_platform_driver(asus_ec_keys_driver);
+
+MODULE_ALIAS("platform:asus-transformer-ec-keys");
+MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
+MODULE_DESCRIPTION("ASUS Transformer's multimedia keys driver");
+MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related
* [PATCH v9 3/7] input: serio: Add driver for ASUS Transformer dock keyboard and touchpad
From: Svyatoslav Ryhel @ 2026-06-25 8:15 UTC (permalink / raw)
To: Rob Herring, Krzysztof Kozlowski, Conor Dooley, Dmitry Torokhov,
Lee Jones, Pavel Machek, Sebastian Reichel, Svyatoslav Ryhel,
Ion Agorria, Michał Mirosław
Cc: devicetree, linux-kernel, linux-input, linux-leds, linux-pm
In-Reply-To: <20260625081529.22447-1-clamor95@gmail.com>
From: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Add input driver for ASUS Transformer dock keyboard and touchpad.
Some keys in ASUS Dock report keycodes that don't make sense according to
their position, this patch modifies the incoming data that is sent to
serio to send proper scancodes.
Co-developed-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
---
drivers/input/serio/Kconfig | 15 ++
drivers/input/serio/Makefile | 1 +
drivers/input/serio/asus-transformer-ec-kbc.c | 168 ++++++++++++++++++
3 files changed, 184 insertions(+)
create mode 100644 drivers/input/serio/asus-transformer-ec-kbc.c
diff --git a/drivers/input/serio/Kconfig b/drivers/input/serio/Kconfig
index 5f15a6462056..fad29b950309 100644
--- a/drivers/input/serio/Kconfig
+++ b/drivers/input/serio/Kconfig
@@ -84,6 +84,21 @@ config SERIO_RPCKBD
To compile this driver as a module, choose M here: the
module will be called rpckbd.
+config SERIO_ASUS_TRANSFORMER_EC
+ tristate "Asus Transformer's Dock keyboard and touchpad controller"
+ depends on MFD_ASUS_TRANSFORMER_EC
+ help
+ Say Y here if you want to use the keyboard and/or touchpad on
+ Asus Transformed's Mobile Dock.
+
+ For keyboard support you also need atkbd driver.
+
+ For touchpad support you also need psmouse driver with Elantech
+ touchpad option enabled.
+
+ To compile this driver as a module, choose M here: the module will
+ be called asus-transformer-ec-kbc.
+
config SERIO_AMBAKMI
tristate "AMBA KMI keyboard controller"
depends on ARM_AMBA
diff --git a/drivers/input/serio/Makefile b/drivers/input/serio/Makefile
index 8ab98f4aa28d..fedc37ee102b 100644
--- a/drivers/input/serio/Makefile
+++ b/drivers/input/serio/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SERIO_SERPORT) += serport.o
obj-$(CONFIG_SERIO_RPCKBD) += rpckbd.o
obj-$(CONFIG_SERIO_SA1111) += sa1111ps2.o
obj-$(CONFIG_SERIO_AMBAKMI) += ambakmi.o
+obj-$(CONFIG_SERIO_ASUS_TRANSFORMER_EC) += asus-transformer-ec-kbc.o
obj-$(CONFIG_SERIO_Q40KBD) += q40kbd.o
obj-$(CONFIG_SERIO_GSCPS2) += gscps2.o
obj-$(CONFIG_HP_SDC) += hp_sdc.o
diff --git a/drivers/input/serio/asus-transformer-ec-kbc.c b/drivers/input/serio/asus-transformer-ec-kbc.c
new file mode 100644
index 000000000000..3ddfa9925b2b
--- /dev/null
+++ b/drivers/input/serio/asus-transformer-ec-kbc.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/i8042.h>
+#include <linux/mfd/asus-transformer-ec.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/serio.h>
+
+struct asus_ec_kbc_data {
+ struct notifier_block nb;
+ struct asusec_core *ec;
+ struct i2c_client *parent;
+ struct serio *sdev[2];
+};
+
+static int asus_ec_kbc_notify(struct notifier_block *nb,
+ unsigned long action, void *data_)
+{
+ struct asus_ec_kbc_data *priv = container_of(nb, struct asus_ec_kbc_data, nb);
+ unsigned int port_idx, n;
+ u8 *data = data_;
+
+ if (action & (ASUSEC_SMI_MASK | ASUSEC_SCI_MASK))
+ return NOTIFY_DONE;
+ else if (action & ASUSEC_AUX_MASK)
+ port_idx = 1;
+ else if (action & (ASUSEC_KBC_MASK | ASUSEC_KEY_MASK))
+ port_idx = 0;
+ else
+ return NOTIFY_DONE;
+
+ /*
+ * The data[0] is the length of the packet including itself. The data[]
+ * buffer has to be at least 3 bytes (length + ctrl + 1 data byte) and
+ * must not exceed the EC buffer size.
+ */
+ if (data[0] < 2 || data[0] > ASUSEC_ENTRY_BUFSIZE)
+ return NOTIFY_BAD;
+
+ n = data[0] - 1;
+ data += 2;
+
+ if (port_idx == 0) {
+ /*
+ * Remap keyboard key codes to match AT layout:
+ * SEARCH: RIGHT-META [E0 27] -> LEFT-ALT [11]
+ * MENU: COMPOSE [E0 2F] -> RIGHT-META [E0 27]
+ */
+ if ((n == 2 || (n == 3 && data[1] == 0xF0)) && data[0] == 0xE0) {
+ u8 *keycode = &data[n - 1];
+
+ switch (*keycode) {
+ case 0x27:
+ *keycode = 0x11;
+ ++data;
+ --n;
+ break;
+ case 0x2F:
+ *keycode = 0x27;
+ break;
+ }
+ }
+ }
+
+ while (n--)
+ serio_interrupt(priv->sdev[port_idx], *data++, 0);
+
+ return NOTIFY_OK;
+}
+
+static int asus_ec_serio_write(struct serio *port, unsigned char data)
+{
+ struct asus_ec_kbc_data *priv = port->port_data;
+
+ return i2c_smbus_write_word_data(priv->parent, ASUSEC_WRITE_BUF,
+ (data << 8) | port->id.extra);
+}
+
+static void asus_ec_serio_remove(void *data)
+{
+ serio_unregister_port(data);
+}
+
+static int asus_ec_register_serio(struct platform_device *pdev, int idx,
+ const char *name, int cmd)
+{
+ struct asus_ec_kbc_data *priv = platform_get_drvdata(pdev);
+ struct i2c_client *parent = priv->parent;
+ struct serio *port = kzalloc_obj(*port);
+
+ if (!port)
+ return -ENOMEM;
+
+ priv->sdev[idx] = port;
+ port->dev.parent = &pdev->dev;
+ port->id.type = SERIO_8042;
+ port->id.extra = cmd & 0xFF;
+ port->write = asus_ec_serio_write;
+ port->port_data = (void *)priv;
+ snprintf(port->name, sizeof(port->name), "%s %s",
+ priv->ec->model, name);
+ snprintf(port->phys, sizeof(port->phys), "i2c-%u-%04x/serio%d",
+ i2c_adapter_id(parent->adapter), parent->addr, idx);
+
+ serio_register_port(port);
+
+ return devm_add_action_or_reset(&pdev->dev, asus_ec_serio_remove, port);
+}
+
+static void asus_ec_notifier_chain_unregister(void *data)
+{
+ struct asus_ec_kbc_data *priv = data;
+ struct asusec_core *ec = priv->ec;
+
+ blocking_notifier_chain_unregister(&ec->notify_list, &priv->nb);
+}
+
+static int asus_ec_kbc_probe(struct platform_device *pdev)
+{
+ struct asusec_core *ec = dev_get_drvdata(pdev->dev.parent);
+ struct asus_ec_kbc_data *priv;
+ int error;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, priv);
+
+ priv->ec = ec;
+ priv->parent = to_i2c_client(pdev->dev.parent);
+
+ error = blocking_notifier_chain_register(&ec->notify_list, &priv->nb);
+ if (error)
+ return dev_err_probe(&pdev->dev, error,
+ "failed to register blocking notifier chain");
+
+ error = devm_add_action_or_reset(&pdev->dev,
+ asus_ec_notifier_chain_unregister,
+ priv);
+ if (error)
+ return error;
+
+ error = asus_ec_register_serio(pdev, 0, "Keyboard", 0);
+ if (error)
+ return error;
+
+ error = asus_ec_register_serio(pdev, 1, "Touchpad", I8042_CMD_AUX_SEND);
+ if (error)
+ return error;
+
+ priv->nb.notifier_call = asus_ec_kbc_notify;
+
+ return 0;
+}
+
+static struct platform_driver asus_ec_kbc_driver = {
+ .driver.name = "asus-transformer-ec-kbc",
+ .probe = asus_ec_kbc_probe,
+};
+module_platform_driver(asus_ec_kbc_driver);
+
+MODULE_ALIAS("platform:asus-transformer-ec-kbc");
+MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
+MODULE_DESCRIPTION("ASUS Transformer's Dock keyboard and touchpad driver");
+MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related
page: next (older) | prev (newer) | latest
- recent:[subjects (threaded)|topics (new)|topics (active)]
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox