[PATCH v1] asm-generic: Provide generic {get,put}_unaligned_{l,b}e24()

[PATCH v1] asm-generic: Provide generic {get,put}_unaligned_{l,b}e24()

[Andy Shevchenko]

There are users in kernel that duplicate {get,put}_unaligned_{l,b}e24()
implementation. Provide generic helpers once for all.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/nvme/host/rdma.c                     |  8 -------
 drivers/nvme/target/rdma.c                   |  6 -----
 drivers/usb/gadget/function/storage_common.h |  5 ----
 include/asm-generic/unaligned.h              | 25 ++++++++++++++++++++
 include/target/target_core_backend.h         |  6 -----
 5 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 3e85c5cacefd..2845118e6e40 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -142,14 +142,6 @@ static void nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc);
 static const struct blk_mq_ops nvme_rdma_mq_ops;
 static const struct blk_mq_ops nvme_rdma_admin_mq_ops;
 
-/* XXX: really should move to a generic header sooner or later.. */
-static inline void put_unaligned_le24(u32 val, u8 *p)
-{
-	*p++ = val;
-	*p++ = val >> 8;
-	*p++ = val >> 16;
-}
-
 static inline int nvme_rdma_queue_idx(struct nvme_rdma_queue *queue)
 {
 	return queue - queue->ctrl->queues;
diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index 37d262a65877..8fcede75e02a 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -143,12 +143,6 @@ static int num_pages(int len)
 	return 1 + (((len - 1) & PAGE_MASK) >> PAGE_SHIFT);
 }
 
-/* XXX: really should move to a generic header sooner or later.. */
-static inline u32 get_unaligned_le24(const u8 *p)
-{
-	return (u32)p[0] | (u32)p[1] << 8 | (u32)p[2] << 16;
-}
-
 static inline bool nvmet_rdma_need_data_in(struct nvmet_rdma_rsp *rsp)
 {
 	return nvme_is_write(rsp->req.cmd) &&
diff --git a/drivers/usb/gadget/function/storage_common.h b/drivers/usb/gadget/function/storage_common.h
index e5e3a2553aaa..bdeb1e233fc9 100644
--- a/drivers/usb/gadget/function/storage_common.h
+++ b/drivers/usb/gadget/function/storage_common.h
@@ -172,11 +172,6 @@ enum data_direction {
 	DATA_DIR_NONE
 };
 
-static inline u32 get_unaligned_be24(u8 *buf)
-{
-	return 0xffffff & (u32) get_unaligned_be32(buf - 1);
-}
-
 static inline struct fsg_lun *fsg_lun_from_dev(struct device *dev)
 {
 	return container_of(dev, struct fsg_lun, dev);
diff --git a/include/asm-generic/unaligned.h b/include/asm-generic/unaligned.h
index 374c940e9be1..dd9f9695d1ba 100644
--- a/include/asm-generic/unaligned.h
+++ b/include/asm-generic/unaligned.h
@@ -33,4 +33,29 @@
 # error need to define endianess
 #endif
 
+/* 24-bit unaligned access is special for now, that's why explicitly here */
+static inline u32 get_unaligned_le24(const u8 *p)
+{
+	return (u32)p[0] | (u32)p[1] << 8 | (u32)p[2] << 16;
+}
+
+static inline void put_unaligned_le24(const u32 val, u8 *p)
+{
+	*p++ = val;
+	*p++ = val >> 8;
+	*p++ = val >> 16;
+}
+
+static inline u32 get_unaligned_be24(const u8 *buf)
+{
+	return (u32)p[0] << 16 | (u32)p[1] << 8 | (u32)p[2];
+}
+
+static inline void put_unaligned_be24(const u32 val, u8 *p)
+{
+	*p++ = val >> 16;
+	*p++ = val >> 8;
+	*p++ = val;
+}
+
 #endif /* __ASM_GENERIC_UNALIGNED_H */
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 51b6f50eabee..1b752d8ea529 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -116,10 +116,4 @@ static inline bool target_dev_configured(struct se_device *se_dev)
 	return !!(se_dev->dev_flags & DF_CONFIGURED);
 }
 
-/* Only use get_unaligned_be24() if reading p - 1 is allowed. */
-static inline uint32_t get_unaligned_be24(const uint8_t *const p)
-{
-	return get_unaligned_be32(p - 1) & 0xffffffU;
-}
-
 #endif /* TARGET_CORE_BACKEND_H */
-- 
2.25.1

Re: [PATCH v1] asm-generic: Provide generic {get,put}_unaligned_{l,b}e24()

[Greg Kroah-Hartman]

On Thu, Mar 12, 2020 at 01:39:41PM +0200, Andy Shevchenko wrote:
> There are users in kernel that duplicate {get,put}_unaligned_{l,b}e24()
> implementation. Provide generic helpers once for all.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/nvme/host/rdma.c                     |  8 -------
>  drivers/nvme/target/rdma.c                   |  6 -----
>  drivers/usb/gadget/function/storage_common.h |  5 ----

For usb:

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH v1] asm-generic: Provide generic {get,put}_unaligned_{l,b}e24()

[Christoph Hellwig]

On Thu, Mar 12, 2020 at 01:39:41PM +0200, Andy Shevchenko wrote:
> There are users in kernel that duplicate {get,put}_unaligned_{l,b}e24()
> implementation. Provide generic helpers once for all.

I have a vague memory of Bart sending a patch like this a while ago,
adding him to verify my theory.

Also is there any good to have this in asm-generic/ vs linux/?

Re: [PATCH v1] asm-generic: Provide generic {get,put}_unaligned_{l,b}e24()

[Andy Shevchenko]

On Thu, Mar 12, 2020 at 03:05:42PM +0100, Christoph Hellwig wrote:
> On Thu, Mar 12, 2020 at 01:39:41PM +0200, Andy Shevchenko wrote:
> > There are users in kernel that duplicate {get,put}_unaligned_{l,b}e24()
> > implementation. Provide generic helpers once for all.
> 
> I have a vague memory of Bart sending a patch like this a while ago,
> adding him to verify my theory.

Thanks!

> Also is there any good to have this in asm-generic/ vs linux/?

For now on it is least invasive. asm-generic/unaligned is a cross point for all
unaligned accessor helpers, since we here do byteshift approach for all
possible variants, I don't see any other header suitable. Or are you talking
about something like linux/unaligned/24bit.h -> #include <...> here?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v1] asm-generic: Provide generic {get, put}_unaligned_{l, b}e24()

[Bart Van Assche]

On 2020-03-12 04:39, Andy Shevchenko wrote:
> There are users in kernel that duplicate {get,put}_unaligned_{l,b}e24()
> implementation. Provide generic helpers once for all.

Hi Andy,

Thanks for having done this work. In case you would not yet have noticed
the patch series that I posted some time ago but for which I did not
have the time to continue working on it, please take a look at
https://lore.kernel.org/lkml/20191028200700.213753-1-bvanassche@acm.org/.

Thanks,

Bart.

Re: [PATCH v1] asm-generic: Provide generic {get, put}_unaligned_{l, b}e24()

[Bart Van Assche]

On 2020-03-12 04:39, Andy Shevchenko wrote:
> +static inline u32 get_unaligned_be24(const u8 *buf)
> +{
> +	return (u32)p[0] << 16 | (u32)p[1] << 8 | (u32)p[2];
> +}

The argument is called 'buf' and the function body dereferences a
pointer called 'p'. Does this even compile?

Bart.

Re: [PATCH v1] asm-generic: Provide generic {get, put}_unaligned_{l, b}e24()

[Andy Shevchenko]

On Thu, Mar 12, 2020 at 08:18:07AM -0700, Bart Van Assche wrote:
> On 2020-03-12 04:39, Andy Shevchenko wrote:
> > There are users in kernel that duplicate {get,put}_unaligned_{l,b}e24()
> > implementation. Provide generic helpers once for all.
> 
> Hi Andy,
> 
> Thanks for having done this work. In case you would not yet have noticed
> the patch series that I posted some time ago but for which I did not
> have the time to continue working on it, please take a look at
> https://lore.kernel.org/lkml/20191028200700.213753-1-bvanassche@acm.org/.

Can you send a new version?

Also, consider to use byteshift to avoid this limitation:
"Only use get_unaligned_be24() if reading p - 1 is allowed."


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v1] asm-generic: Provide generic {get, put}_unaligned_{l, b}e24()

[Bart Van Assche]

On 3/12/20 9:25 AM, Andy Shevchenko wrote:
> On Thu, Mar 12, 2020 at 08:18:07AM -0700, Bart Van Assche wrote:
>> On 2020-03-12 04:39, Andy Shevchenko wrote:
>>> There are users in kernel that duplicate {get,put}_unaligned_{l,b}e24()
>>> implementation. Provide generic helpers once for all.
>>
>> Hi Andy,
>>
>> Thanks for having done this work. In case you would not yet have noticed
>> the patch series that I posted some time ago but for which I did not
>> have the time to continue working on it, please take a look at
>> https://lore.kernel.org/lkml/20191028200700.213753-1-bvanassche@acm.org/.
> 
> Can you send a new version?
> 
> Also, consider to use byteshift to avoid this limitation:
> "Only use get_unaligned_be24() if reading p - 1 is allowed."

Sure, I will do that and I will also add you to the Cc-list of the patch 
series.

Thanks,

Bart.

Re: [PATCH v1] asm-generic: Provide generic {get, put}_unaligned_{l, b}e24()

[Martin K. Petersen]

Bart,

> Martin, can I send the second version of my patch series to you or do
> you perhaps prefer that I send it to another kernel maintainer? I'm
> considering to include the following patches:

Happy to take it.

-- 
Martin K. Petersen	Oracle Linux Engineering