[PATCH v5 0/9] driver core: Fix some race conditions

[PATCH v5 0/9] driver core: Fix some race conditions

[Douglas Anderson]

The main goal of this series is to fix the observed bug talked about
in the first patch ("driver core: Don't let a device probe until it's
ready"). That patch fixes a problem that has been observed in the real
world and could land even if the rest of the patches are found
unacceptable or need to be spun.

That said, during patch review Danilo correctly pointed out that many
of the bitfield accesses in "struct device" are unsafe. I added a
bunch of patches in the series to address each one.

Danilo said he's most worried about "can_match", so I put that one
first. After that, I tried to transition bitfields to flags in reverse
order to when the bitfield was added.

Even if transitioning from bitfields to flags isn't truly needed for
correctness, it seems silly (and wasteful of space in struct device)
to have some in bitfields and some as flags. Thus I didn't spend time
for each bitfield showing that it's truly needed for correctness.

Transition was done semi manually. Presumably someone skilled at
coccinelle could do a better job, but I just used sed in a heavy-
handed manner and then reviewed/fixed the results, undoing anything my
script got wrong. My terrible/ugly script was:

var=can_match
caps="${var^^}"
for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
  echo $f
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f"
done

From v3 to v4, I transitioned to accessor functions with another ugly
sed script. I had git format the old patches, then transformed them
with:

for f in *.patch; do
  echo $f
  sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
  sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
done

...and then did a few manual touchups for spacing.

I only marked the first patch as a "Fix" since it is the only one
fixing observed problems. Other patches could be considered fixes too
if folks want.

I tested the first patch in the series backported to kernel 6.6 on the
Pixel phone that was experiencing the race. I added extra printouts to
make sure that the problem was hitting / addressed. The rest of the
patches are tested with allmodconfig with arm32, arm64, ppc, and
x86. I boot tested on an arm64 Chromebook running mainline.

Changes in v5:
- ready_to_prove => ready_to_probe typo
- device_lock() while calling dev_set_ready_to_probe()
- Add comment before "can_match = true" from Danilo.
- undef __create_dev_flag_accessors

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- Use a new "flags" bitfield
- Add missing \n in probe error message

Changes in v2:
- Instead of adjusting the ordering, use "ready_to_probe" flag

Douglas Anderson (9):
  driver core: Don't let a device probe until it's ready
  driver core: Replace dev->can_match with dev_can_match()
  driver core: Replace dev->dma_iommu with dev_dma_iommu()
  driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
  driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
  driver core: Replace dev->state_synced with dev_state_synced()
  driver core: Replace dev->dma_coherent with dev_dma_coherent()
  driver core: Replace dev->of_node_reused with dev_of_node_reused()
  driver core: Replace dev->offline + ->offline_disabled with accessors

 arch/arc/mm/dma.c                             |   4 +-
 arch/arm/mach-highbank/highbank.c             |   2 +-
 arch/arm/mach-mvebu/coherency.c               |   2 +-
 arch/arm/mm/dma-mapping-nommu.c               |   4 +-
 arch/arm/mm/dma-mapping.c                     |  28 ++--
 arch/arm64/kernel/cpufeature.c                |   2 +-
 arch/arm64/mm/dma-mapping.c                   |   2 +-
 arch/mips/mm/dma-noncoherent.c                |   2 +-
 arch/powerpc/kernel/dma-iommu.c               |   8 +-
 .../platforms/pseries/hotplug-memory.c        |   4 +-
 arch/riscv/mm/dma-noncoherent.c               |   2 +-
 drivers/acpi/scan.c                           |   2 +-
 drivers/base/core.c                           |  55 +++++---
 drivers/base/cpu.c                            |   4 +-
 drivers/base/dd.c                             |  36 ++++--
 drivers/base/memory.c                         |   2 +-
 drivers/base/pinctrl.c                        |   2 +-
 drivers/base/platform.c                       |   2 +-
 drivers/dma/ti/k3-udma-glue.c                 |   6 +-
 drivers/dma/ti/k3-udma.c                      |   6 +-
 drivers/iommu/dma-iommu.c                     |   9 +-
 drivers/iommu/iommu.c                         |   5 +-
 drivers/net/pcs/pcs-xpcs-plat.c               |   2 +-
 drivers/of/device.c                           |   6 +-
 drivers/pci/of.c                              |   2 +-
 drivers/pci/pwrctrl/core.c                    |   2 +-
 drivers/regulator/bq257xx-regulator.c         |   2 +-
 drivers/regulator/rk808-regulator.c           |   2 +-
 drivers/tty/serial/serial_base_bus.c          |   2 +-
 drivers/usb/gadget/udc/aspeed-vhub/dev.c      |   2 +-
 include/linux/device.h                        | 122 ++++++++++++------
 include/linux/dma-map-ops.h                   |   6 +-
 include/linux/dma-mapping.h                   |   2 +-
 include/linux/iommu-dma.h                     |   3 +-
 kernel/cpu.c                                  |   4 +-
 kernel/dma/mapping.c                          |  12 +-
 mm/hmm.c                                      |   2 +-
 37 files changed, 218 insertions(+), 142 deletions(-)

-- 
2.53.0.1213.gd9a14994de-goog

[PATCH v5 1/9] driver core: Don't let a device probe until it's ready

[Douglas Anderson]

The moment we link a "struct device" into the list of devices for the
bus, it's possible probe can happen. This is because another thread
can load the driver at any time and that can cause the device to
probe. This has been seen in practice with a stack crawl that looks
like this [1]:

  really_probe()
  __driver_probe_device()
  driver_probe_device()
  __driver_attach()
  bus_for_each_dev()
  driver_attach()
  bus_add_driver()
  driver_register()
  __platform_driver_register()
  init_module() [some module]
  do_one_initcall()
  do_init_module()
  load_module()
  __arm64_sys_finit_module()
  invoke_syscall()

As a result of the above, it was seen that device_links_driver_bound()
could be called for the device before "dev->fwnode->dev" was
assigned. This prevented __fw_devlink_pickup_dangling_consumers() from
being called which meant that other devices waiting on our driver's
sub-nodes were stuck deferring forever.

It's believed that this problem is showing up suddenly for two
reasons:
1. Android has recently (last ~1 year) implemented an optimization to
   the order it loads modules [2]. When devices opt-in to this faster
   loading, modules are loaded one-after-the-other very quickly. This
   is unlike how other distributions do it. The reproduction of this
   problem has only been seen on devices that opt-in to Android's
   "parallel module loading".
2. Android devices typically opt-in to fw_devlink, and the most
   noticeable issue is the NULL "dev->fwnode->dev" in
   device_links_driver_bound(). fw_devlink is somewhat new code and
   also not in use by all Linux devices.

Even though the specific symptom where "dev->fwnode->dev" wasn't
assigned could be fixed by moving that assignment higher in
device_add(), other parts of device_add() (like the call to
device_pm_add()) are also important to run before probe. Only moving
the "dev->fwnode->dev" assignment would likely fix the current
symptoms but lead to difficult-to-debug problems in the future.

Fix the problem by preventing probe until device_add() has run far
enough that the device is ready to probe. If somehow we end up trying
to probe before we're allowed, __driver_probe_device() will return
-EPROBE_DEFER which will make certain the device is noticed.

In the race condition that was seen with Android's faster module
loading, we will temporarily add the device to the deferred list and
then take it off immediately when device_add() probes the device.

Instead of adding another flag to the bitfields already in "struct
device", instead add a new "flags" field and use that. This allows us
to freely change the bit from different thread without worrying about
corrupting nearby bits (and means threads changing other bit won't
corrupt us).

[1] Captured on a machine running a downstream 6.6 kernel
[2] https://cs.android.com/android/platform/superproject/main/+/main:system/core/libmodprobe/libmodprobe.cpp?q=LoadModulesParallel

Cc: stable@vger.kernel.org
Fixes: 2023c610dc54 ("Driver core: add new device to bus's list before probing")
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
v1: https://lore.kernel.org/r/20260320200656.RFC.1.Id750b0fbcc94f23ed04b7aecabcead688d0d8c17@changeid
v2: https://lore.kernel.org/r/20260330072839.v2.1.Id750b0fbcc94f23ed04b7aecabcead688d0d8c17@changeid
v3: https://lore.kernel.org/r/20260403005005.30424-1-dianders@chromium.org/
v4: https://lore.kernel.org/r/20260404000644.522677-1-dianders@chromium.org

As of v2 this feels like a very safe change. It doesn't change the
ordering of any steps of probe and it _just_ prevents the early probe
from happening.

I ran tests where I turned the printout "Device not ready_to_probe" on
and I could see the printout happening, evidence of the race occurring
from other printouts, and things successfully being resolved.

I kept Alan and Rafael's Reviewed-by tags in v3 even though I changed
the implementation to use "flags" as per Danilo's request. This didn't
seem like a major enough change to remove tags, but please shout if
you'd like your tag removed.

Changes in v5:
- ready_to_prove => ready_to_probe typo
- device_lock() while calling dev_set_ready_to_probe()
- Add comment before "can_match = true" from Danilo.
- undef __create_dev_flag_accessors

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- Use a new "flags" bitfield
- Add missing \n in probe error message

Changes in v2:
- Instead of adjusting the ordering, use "ready_to_probe" flag

 drivers/base/core.c    | 15 ++++++++++++++
 drivers/base/dd.c      | 20 +++++++++++++++++++
 include/linux/device.h | 44 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 79 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 09b98f02f559..984d6bfbd6e4 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3688,6 +3688,21 @@ int device_add(struct device *dev)
 		fw_devlink_link_device(dev);
 	}
 
+	/*
+	 * The moment the device was linked into the bus's "klist_devices" in
+	 * bus_add_device() then it's possible that probe could have been
+	 * attempted in a different thread via userspace loading a driver
+	 * matching the device. "ready_to_probe" being unset would have
+	 * blocked those attempts. Now that all of the above initialization has
+	 * happened, unblock probe. If probe happens through another thread
+	 * after this point but before bus_probe_device() runs then it's fine.
+	 * bus_probe_device() -> device_initial_probe() -> __device_attach()
+	 * will notice (under device_lock) that the device is already bound.
+	 */
+	device_lock(dev);
+	dev_set_ready_to_probe(dev);
+	device_unlock(dev);
+
 	bus_probe_device(dev);
 
 	/*
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 37c7e54e0e4c..ec7ef9c5d62e 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -848,6 +848,26 @@ static int __driver_probe_device(const struct device_driver *drv, struct device
 	if (dev->driver)
 		return -EBUSY;
 
+	/*
+	 * In device_add(), the "struct device" gets linked into the subsystem's
+	 * list of devices and broadcast to userspace (via uevent) before we're
+	 * quite ready to probe. Those open pathways to driver probe before
+	 * we've finished enough of device_add() to reliably support probe.
+	 * Detect this and tell other pathways to try again later. device_add()
+	 * itself will also try to probe immediately after setting
+	 * "ready_to_probe".
+	 */
+	if (!dev_ready_to_probe(dev))
+		return dev_err_probe(dev, -EPROBE_DEFER, "Device not ready to probe\n");
+
+	/*
+	 * Set can_match = true after calling dev_ready_to_probe(), so
+	 * driver_deferred_probe_add() won't actually add the device to the
+	 * deferred probe list when dev_ready_to_probe() returns false.
+	 *
+	 * When dev_ready_to_probe() returns false, it means that device_add()
+	 * will do another probe() attempt for us.
+	 */
 	dev->can_match = true;
 	dev_dbg(dev, "bus: '%s': %s: matched device with driver %s\n",
 		drv->bus->name, __func__, drv->name);
diff --git a/include/linux/device.h b/include/linux/device.h
index e65d564f01cd..f27ed6eb87a9 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -458,6 +458,21 @@ struct device_physical_location {
 	bool lid;
 };
 
+/**
+ * enum struct_device_flags - Flags in struct device
+ *
+ * Each flag should have a set of accessor functions created via
+ * __create_dev_flag_accessors() for each access.
+ *
+ * @DEV_FLAG_READY_TO_PROBE: If set then device_add() has finished enough
+ *		initialization that probe could be called.
+ */
+enum struct_device_flags {
+	DEV_FLAG_READY_TO_PROBE = 0,
+
+	DEV_FLAG_COUNT
+};
+
 /**
  * struct device - The basic device structure
  * @parent:	The device's "parent" device, the device to which it is attached.
@@ -553,6 +568,7 @@ struct device_physical_location {
  * @dma_skip_sync: DMA sync operations can be skipped for coherent buffers.
  * @dma_iommu: Device is using default IOMMU implementation for DMA and
  *		doesn't rely on dma_ops structure.
+ * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
  * instance of struct device. The device structure contains the information
@@ -675,8 +691,36 @@ struct device {
 #ifdef CONFIG_IOMMU_DMA
 	bool			dma_iommu:1;
 #endif
+
+	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
 };
 
+#define __create_dev_flag_accessors(accessor_name, flag_name) \
+static inline bool dev_##accessor_name(const struct device *dev) \
+{ \
+	return test_bit(flag_name, dev->flags); \
+} \
+static inline void dev_set_##accessor_name(struct device *dev) \
+{ \
+	set_bit(flag_name, dev->flags); \
+} \
+static inline void dev_clear_##accessor_name(struct device *dev) \
+{ \
+	clear_bit(flag_name, dev->flags); \
+} \
+static inline void dev_assign_##accessor_name(struct device *dev, bool value) \
+{ \
+	assign_bit(flag_name, dev->flags, value); \
+} \
+static inline bool dev_test_and_set_##accessor_name(struct device *dev) \
+{ \
+	return test_and_set_bit(flag_name, dev->flags); \
+}
+
+__create_dev_flag_accessors(ready_to_probe, DEV_FLAG_READY_TO_PROBE);
+
+#undef __create_dev_flag_accessors
+
 /**
  * struct device_link - Device link representation.
  * @supplier: The device on the supplier end of the link.
-- 
2.53.0.1213.gd9a14994de-goog

[PATCH v5 2/9] driver core: Replace dev->can_match with dev_can_match()

[Douglas Anderson]

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "can_match" over to the "flags" field
so modifications are safe.

Cc: Saravana Kannan <saravanak@kernel.org>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

(no changes since v4)

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 drivers/base/core.c    | 10 +++++-----
 drivers/base/dd.c      | 10 +++++-----
 include/linux/device.h |  9 +++++----
 3 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 984d6bfbd6e4..db5aec9e6a2b 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1011,7 +1011,7 @@ static void device_links_missing_supplier(struct device *dev)
 
 static bool dev_is_best_effort(struct device *dev)
 {
-	return (fw_devlink_best_effort && dev->can_match) ||
+	return (fw_devlink_best_effort && dev_can_match(dev)) ||
 		(dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
 }
 
@@ -1079,7 +1079,7 @@ int device_links_check_suppliers(struct device *dev)
 
 			if (dev_is_best_effort(dev) &&
 			    device_link_test(link, DL_FLAG_INFERRED) &&
-			    !link->supplier->can_match) {
+			    !dev_can_match(link->supplier)) {
 				ret = -EAGAIN;
 				continue;
 			}
@@ -1370,7 +1370,7 @@ void device_links_driver_bound(struct device *dev)
 		} else if (dev_is_best_effort(dev) &&
 			   device_link_test(link, DL_FLAG_INFERRED) &&
 			   link->status != DL_STATE_CONSUMER_PROBE &&
-			   !link->supplier->can_match) {
+			   !dev_can_match(link->supplier)) {
 			/*
 			 * When dev_is_best_effort() is true, we ignore device
 			 * links to suppliers that don't have a driver.  If the
@@ -1758,7 +1758,7 @@ static int fw_devlink_no_driver(struct device *dev, void *data)
 {
 	struct device_link *link = to_devlink(dev);
 
-	if (!link->supplier->can_match)
+	if (!dev_can_match(link->supplier))
 		fw_devlink_relax_link(link);
 
 	return 0;
@@ -3710,7 +3710,7 @@ int device_add(struct device *dev)
 	 * match with any driver, don't block its consumers from probing in
 	 * case the consumer device is able to operate without this supplier.
 	 */
-	if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
+	if (dev->fwnode && fw_devlink_drv_reg_done && !dev_can_match(dev))
 		fw_devlink_unblock_consumers(dev);
 
 	if (parent)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index ec7ef9c5d62e..70fa0b13e74f 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -132,7 +132,7 @@ static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
 
 void driver_deferred_probe_add(struct device *dev)
 {
-	if (!dev->can_match)
+	if (!dev_can_match(dev))
 		return;
 
 	mutex_lock(&deferred_probe_mutex);
@@ -861,14 +861,14 @@ static int __driver_probe_device(const struct device_driver *drv, struct device
 		return dev_err_probe(dev, -EPROBE_DEFER, "Device not ready to probe\n");
 
 	/*
-	 * Set can_match = true after calling dev_ready_to_probe(), so
+	 * Call dev_set_can_match() after calling dev_ready_to_probe(), so
 	 * driver_deferred_probe_add() won't actually add the device to the
 	 * deferred probe list when dev_ready_to_probe() returns false.
 	 *
 	 * When dev_ready_to_probe() returns false, it means that device_add()
 	 * will do another probe() attempt for us.
 	 */
-	dev->can_match = true;
+	dev_set_can_match(dev);
 	dev_dbg(dev, "bus: '%s': %s: matched device with driver %s\n",
 		drv->bus->name, __func__, drv->name);
 
@@ -1014,7 +1014,7 @@ static int __device_attach_driver(struct device_driver *drv, void *_data)
 		return 0;
 	} else if (ret == -EPROBE_DEFER) {
 		dev_dbg(dev, "Device match requests probe deferral\n");
-		dev->can_match = true;
+		dev_set_can_match(dev);
 		driver_deferred_probe_add(dev);
 		/*
 		 * Device can't match with a driver right now, so don't attempt
@@ -1266,7 +1266,7 @@ static int __driver_attach(struct device *dev, void *data)
 		return 0;
 	} else if (ret == -EPROBE_DEFER) {
 		dev_dbg(dev, "Device match requests probe deferral\n");
-		dev->can_match = true;
+		dev_set_can_match(dev);
 		driver_deferred_probe_add(dev);
 		/*
 		 * Driver could not match with device, but may match with
diff --git a/include/linux/device.h b/include/linux/device.h
index f27ed6eb87a9..38f4316b3cde 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -466,9 +466,13 @@ struct device_physical_location {
  *
  * @DEV_FLAG_READY_TO_PROBE: If set then device_add() has finished enough
  *		initialization that probe could be called.
+ * @DEV_FLAG_CAN_MATCH: The device has matched with a driver at least once or it
+ *		is in a bus (like AMBA) which can't check for matching drivers
+ *		until other devices probe successfully.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
+	DEV_FLAG_CAN_MATCH = 1,
 
 	DEV_FLAG_COUNT
 };
@@ -555,9 +559,6 @@ enum struct_device_flags {
  * @state_synced: The hardware state of this device has been synced to match
  *		  the software state of this device by calling the driver/bus
  *		  sync_state() callback.
- * @can_match:	The device has matched with a driver at least once or it is in
- *		a bus (like AMBA) which can't check for matching drivers until
- *		other devices probe successfully.
  * @dma_coherent: this particular device is dma coherent, even if the
  *		architecture supports non-coherent devices.
  * @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the
@@ -676,7 +677,6 @@ struct device {
 	bool			offline:1;
 	bool			of_node_reused:1;
 	bool			state_synced:1;
-	bool			can_match:1;
 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
@@ -718,6 +718,7 @@ static inline bool dev_test_and_set_##accessor_name(struct device *dev) \
 }
 
 __create_dev_flag_accessors(ready_to_probe, DEV_FLAG_READY_TO_PROBE);
+__create_dev_flag_accessors(can_match, DEV_FLAG_CAN_MATCH);
 
 #undef __create_dev_flag_accessors
 
-- 
2.53.0.1213.gd9a14994de-goog

[PATCH v5 3/9] driver core: Replace dev->dma_iommu with dev_dma_iommu()

[Douglas Anderson]

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "dma_iommu" over to the "flags" field
so modifications are safe.

Cc: Leon Romanovsky <leon@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

NOTE: even though previously we only took up a bit if
CONFIG_IOMMU_DMA, in this change I reserve the bit unconditionally.
While we could get the "dynamic" behavior by changing the flags
definition to be an unnumbered "enum", Greg has requested that the
numbers be stable. This also allows us to move one "#ifdef" to an
"if", getting better compile-time testing of both sides of the "if".

(no changes since v4)

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 drivers/iommu/dma-iommu.c | 9 ++++++---
 drivers/iommu/iommu.c     | 5 ++---
 include/linux/device.h    | 9 ++++-----
 include/linux/iommu-dma.h | 3 ++-
 4 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 94d514169642..036994069b80 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -2112,18 +2112,21 @@ EXPORT_SYMBOL_GPL(dma_iova_destroy);
 
 void iommu_setup_dma_ops(struct device *dev, struct iommu_domain *domain)
 {
+	bool dma_iommu;
+
 	if (dev_is_pci(dev))
 		dev->iommu->pci_32bit_workaround = !iommu_dma_forcedac;
 
-	dev->dma_iommu = iommu_is_dma_domain(domain);
-	if (dev->dma_iommu && iommu_dma_init_domain(domain, dev))
+	dma_iommu = iommu_is_dma_domain(domain);
+	dev_assign_dma_iommu(dev, dma_iommu);
+	if (dma_iommu && iommu_dma_init_domain(domain, dev))
 		goto out_err;
 
 	return;
 out_err:
 	pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
 		dev_name(dev));
-	dev->dma_iommu = false;
+	dev_clear_dma_iommu(dev);
 }
 
 static bool has_msi_cookie(const struct iommu_domain *domain)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 50718ab810a4..8dc50a0eee85 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -589,9 +589,8 @@ static void iommu_deinit_device(struct device *dev)
 	dev->iommu_group = NULL;
 	module_put(ops->owner);
 	dev_iommu_free(dev);
-#ifdef CONFIG_IOMMU_DMA
-	dev->dma_iommu = false;
-#endif
+	if (IS_ENABLED(CONFIG_IOMMU_DMA))
+		dev_clear_dma_iommu(dev);
 }
 
 static struct iommu_domain *pasid_array_entry_to_domain(void *entry)
diff --git a/include/linux/device.h b/include/linux/device.h
index 38f4316b3cde..620306e8380a 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -469,10 +469,13 @@ struct device_physical_location {
  * @DEV_FLAG_CAN_MATCH: The device has matched with a driver at least once or it
  *		is in a bus (like AMBA) which can't check for matching drivers
  *		until other devices probe successfully.
+ * @DEV_FLAG_DMA_IOMMU: Device is using default IOMMU implementation for DMA and
+ *		doesn't rely on dma_ops structure.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
 	DEV_FLAG_CAN_MATCH = 1,
+	DEV_FLAG_DMA_IOMMU = 2,
 
 	DEV_FLAG_COUNT
 };
@@ -567,8 +570,6 @@ enum struct_device_flags {
  *		for dma allocations.  This flag is managed by the dma ops
  *		instance from ->dma_supported.
  * @dma_skip_sync: DMA sync operations can be skipped for coherent buffers.
- * @dma_iommu: Device is using default IOMMU implementation for DMA and
- *		doesn't rely on dma_ops structure.
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
@@ -688,9 +689,6 @@ struct device {
 #ifdef CONFIG_DMA_NEED_SYNC
 	bool			dma_skip_sync:1;
 #endif
-#ifdef CONFIG_IOMMU_DMA
-	bool			dma_iommu:1;
-#endif
 
 	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
 };
@@ -719,6 +717,7 @@ static inline bool dev_test_and_set_##accessor_name(struct device *dev) \
 
 __create_dev_flag_accessors(ready_to_probe, DEV_FLAG_READY_TO_PROBE);
 __create_dev_flag_accessors(can_match, DEV_FLAG_CAN_MATCH);
+__create_dev_flag_accessors(dma_iommu, DEV_FLAG_DMA_IOMMU);
 
 #undef __create_dev_flag_accessors
 
diff --git a/include/linux/iommu-dma.h b/include/linux/iommu-dma.h
index a92b3ff9b934..060f6e23ab3c 100644
--- a/include/linux/iommu-dma.h
+++ b/include/linux/iommu-dma.h
@@ -7,12 +7,13 @@
 #ifndef _LINUX_IOMMU_DMA_H
 #define _LINUX_IOMMU_DMA_H
 
+#include <linux/device.h>
 #include <linux/dma-direction.h>
 
 #ifdef CONFIG_IOMMU_DMA
 static inline bool use_dma_iommu(struct device *dev)
 {
-	return dev->dma_iommu;
+	return dev_dma_iommu(dev);
 }
 #else
 static inline bool use_dma_iommu(struct device *dev)
-- 
2.53.0.1213.gd9a14994de-goog

[PATCH v5 4/9] driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()

[Douglas Anderson]

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "dma_skip_sync" over to the "flags"
field so modifications are safe.

Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

NOTE: even though previously we only took up a bit if
CONFIG_DMA_NEED_SYNC, in this change I reserve the bit
unconditionally. While we could get the "dynamic" behavior by changing
the flags definition to be an unnumbered "enum", Greg has requested
that the numbers be stable.

(no changes since v4)

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 include/linux/device.h      | 8 ++++----
 include/linux/dma-map-ops.h | 4 ++--
 include/linux/dma-mapping.h | 2 +-
 kernel/dma/mapping.c        | 8 ++++----
 mm/hmm.c                    | 2 +-
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/linux/device.h b/include/linux/device.h
index 620306e8380a..c38593cf2583 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -471,11 +471,14 @@ struct device_physical_location {
  *		until other devices probe successfully.
  * @DEV_FLAG_DMA_IOMMU: Device is using default IOMMU implementation for DMA and
  *		doesn't rely on dma_ops structure.
+ * @DEV_FLAG_DMA_SKIP_SYNC: DMA sync operations can be skipped for coherent
+ *		buffers.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
 	DEV_FLAG_CAN_MATCH = 1,
 	DEV_FLAG_DMA_IOMMU = 2,
+	DEV_FLAG_DMA_SKIP_SYNC = 3,
 
 	DEV_FLAG_COUNT
 };
@@ -569,7 +572,6 @@ enum struct_device_flags {
  *		and optionall (if the coherent mask is large enough) also
  *		for dma allocations.  This flag is managed by the dma ops
  *		instance from ->dma_supported.
- * @dma_skip_sync: DMA sync operations can be skipped for coherent buffers.
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
@@ -686,9 +688,6 @@ struct device {
 #ifdef CONFIG_DMA_OPS_BYPASS
 	bool			dma_ops_bypass : 1;
 #endif
-#ifdef CONFIG_DMA_NEED_SYNC
-	bool			dma_skip_sync:1;
-#endif
 
 	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
 };
@@ -718,6 +717,7 @@ static inline bool dev_test_and_set_##accessor_name(struct device *dev) \
 __create_dev_flag_accessors(ready_to_probe, DEV_FLAG_READY_TO_PROBE);
 __create_dev_flag_accessors(can_match, DEV_FLAG_CAN_MATCH);
 __create_dev_flag_accessors(dma_iommu, DEV_FLAG_DMA_IOMMU);
+__create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
 
 #undef __create_dev_flag_accessors
 
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 60b63756df82..edd7de60a957 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -245,8 +245,8 @@ static inline void dma_reset_need_sync(struct device *dev)
 {
 #ifdef CONFIG_DMA_NEED_SYNC
 	/* Reset it only once so that the function can be called on hotpath */
-	if (unlikely(dev->dma_skip_sync))
-		dev->dma_skip_sync = false;
+	if (unlikely(dev_dma_skip_sync(dev)))
+		dev_clear_dma_skip_sync(dev);
 #endif
 }
 
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 99ef042ecdb4..ef4feb2b37d8 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -419,7 +419,7 @@ bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr);
 static inline bool dma_dev_need_sync(const struct device *dev)
 {
 	/* Always call DMA sync operations when debugging is enabled */
-	return !dev->dma_skip_sync || IS_ENABLED(CONFIG_DMA_API_DEBUG);
+	return !dev_dma_skip_sync(dev) || IS_ENABLED(CONFIG_DMA_API_DEBUG);
 }
 
 static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 6d3dd0bd3a88..76fc65d1a8a4 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -467,7 +467,7 @@ bool dma_need_unmap(struct device *dev)
 {
 	if (!dma_map_direct(dev, get_dma_ops(dev)))
 		return true;
-	if (!dev->dma_skip_sync)
+	if (!dev_dma_skip_sync(dev))
 		return true;
 	return IS_ENABLED(CONFIG_DMA_API_DEBUG);
 }
@@ -483,16 +483,16 @@ static void dma_setup_need_sync(struct device *dev)
 		 * mapping, if any. During the device initialization, it's
 		 * enough to check only for the DMA coherence.
 		 */
-		dev->dma_skip_sync = dev_is_dma_coherent(dev);
+		dev_assign_dma_skip_sync(dev, dev_is_dma_coherent(dev));
 	else if (!ops->sync_single_for_device && !ops->sync_single_for_cpu &&
 		 !ops->sync_sg_for_device && !ops->sync_sg_for_cpu)
 		/*
 		 * Synchronization is not possible when none of DMA sync ops
 		 * is set.
 		 */
-		dev->dma_skip_sync = true;
+		dev_set_dma_skip_sync(dev);
 	else
-		dev->dma_skip_sync = false;
+		dev_clear_dma_skip_sync(dev);
 }
 #else /* !CONFIG_DMA_NEED_SYNC */
 static inline void dma_setup_need_sync(struct device *dev) { }
diff --git a/mm/hmm.c b/mm/hmm.c
index 5955f2f0c83d..c72c9ddfdb2f 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -709,7 +709,7 @@ int hmm_dma_map_alloc(struct device *dev, struct hmm_dma_map *map,
 	 * best approximation to ensure no swiotlb buffering happens.
 	 */
 #ifdef CONFIG_DMA_NEED_SYNC
-	dma_need_sync = !dev->dma_skip_sync;
+	dma_need_sync = !dev_dma_skip_sync(dev);
 #endif /* CONFIG_DMA_NEED_SYNC */
 	if (dma_need_sync || dma_addressing_limited(dev))
 		return -EOPNOTSUPP;
-- 
2.53.0.1213.gd9a14994de-goog

[PATCH v5 5/9] driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()

[Douglas Anderson]

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "dma_ops_bypass" over to the "flags"
field so modifications are safe.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

NOTE: even though previously we only took up a bit if
CONFIG_DMA_OPS_BYPASS, in this change I reserve the bit
unconditionally.  While we could get the "dynamic" behavior by
changing the flags definition to be an unnumbered "enum", Greg has
requested that the numbers be stable. This also allows us to move one
"#ifdef" to an "if", getting better compile-time testing of both sides
of the "if".

(no changes since v4)

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 arch/powerpc/kernel/dma-iommu.c |  8 ++++----
 include/linux/device.h          | 15 +++++++--------
 kernel/dma/mapping.c            |  4 +---
 3 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/kernel/dma-iommu.c b/arch/powerpc/kernel/dma-iommu.c
index 73e10bd4d56d..6d1899b38c3d 100644
--- a/arch/powerpc/kernel/dma-iommu.c
+++ b/arch/powerpc/kernel/dma-iommu.c
@@ -67,7 +67,7 @@ bool arch_dma_unmap_sg_direct(struct device *dev, struct scatterlist *sg,
 }
 bool arch_dma_alloc_direct(struct device *dev)
 {
-	if (dev->dma_ops_bypass)
+	if (dev_dma_ops_bypass(dev))
 		return true;
 
 	return false;
@@ -75,7 +75,7 @@ bool arch_dma_alloc_direct(struct device *dev)
 
 bool arch_dma_free_direct(struct device *dev, dma_addr_t dma_handle)
 {
-	if (!dev->dma_ops_bypass)
+	if (!dev_dma_ops_bypass(dev))
 		return false;
 
 	return is_direct_handle(dev, dma_handle);
@@ -164,7 +164,7 @@ int dma_iommu_dma_supported(struct device *dev, u64 mask)
 		 * fixed ops will be used for RAM. This is limited by
 		 * bus_dma_limit which is set when RAM is pre-mapped.
 		 */
-		dev->dma_ops_bypass = true;
+		dev_set_dma_ops_bypass(dev);
 		dev_info(dev, "iommu: 64-bit OK but direct DMA is limited by %llx\n",
 			 dev->bus_dma_limit);
 		return 1;
@@ -185,7 +185,7 @@ int dma_iommu_dma_supported(struct device *dev, u64 mask)
 	}
 
 	dev_dbg(dev, "iommu: not 64-bit, using default ops\n");
-	dev->dma_ops_bypass = false;
+	dev_clear_dma_ops_bypass(dev);
 	return 1;
 }
 
diff --git a/include/linux/device.h b/include/linux/device.h
index c38593cf2583..1c43ff695e83 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -473,12 +473,18 @@ struct device_physical_location {
  *		doesn't rely on dma_ops structure.
  * @DEV_FLAG_DMA_SKIP_SYNC: DMA sync operations can be skipped for coherent
  *		buffers.
+ * @DEV_FLAG_DMA_OPS_BYPASS: If set then the dma_ops are bypassed for the
+ *		streaming DMA operations (->map_* / ->unmap_* / ->sync_*), and
+ *		optional (if the coherent mask is large enough) also for dma
+ *		allocations. This flag is managed by the dma ops instance from
+ *		->dma_supported.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
 	DEV_FLAG_CAN_MATCH = 1,
 	DEV_FLAG_DMA_IOMMU = 2,
 	DEV_FLAG_DMA_SKIP_SYNC = 3,
+	DEV_FLAG_DMA_OPS_BYPASS = 4,
 
 	DEV_FLAG_COUNT
 };
@@ -567,11 +573,6 @@ enum struct_device_flags {
  *		  sync_state() callback.
  * @dma_coherent: this particular device is dma coherent, even if the
  *		architecture supports non-coherent devices.
- * @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the
- *		streaming DMA operations (->map_* / ->unmap_* / ->sync_*),
- *		and optionall (if the coherent mask is large enough) also
- *		for dma allocations.  This flag is managed by the dma ops
- *		instance from ->dma_supported.
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
@@ -685,9 +686,6 @@ struct device {
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
 	bool			dma_coherent:1;
 #endif
-#ifdef CONFIG_DMA_OPS_BYPASS
-	bool			dma_ops_bypass : 1;
-#endif
 
 	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
 };
@@ -718,6 +716,7 @@ __create_dev_flag_accessors(ready_to_probe, DEV_FLAG_READY_TO_PROBE);
 __create_dev_flag_accessors(can_match, DEV_FLAG_CAN_MATCH);
 __create_dev_flag_accessors(dma_iommu, DEV_FLAG_DMA_IOMMU);
 __create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
+__create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
 
 #undef __create_dev_flag_accessors
 
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 76fc65d1a8a4..30bf8455730a 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -126,11 +126,9 @@ static bool dma_go_direct(struct device *dev, dma_addr_t mask,
 	if (likely(!ops))
 		return true;
 
-#ifdef CONFIG_DMA_OPS_BYPASS
-	if (dev->dma_ops_bypass)
+	if (IS_ENABLED(CONFIG_DMA_OPS_BYPASS) && dev_dma_ops_bypass(dev))
 		return min_not_zero(mask, dev->bus_dma_limit) >=
 			    dma_direct_get_required_mask(dev);
-#endif
 	return false;
 }
 
-- 
2.53.0.1213.gd9a14994de-goog

[PATCH v5 6/9] driver core: Replace dev->state_synced with dev_state_synced()

[Douglas Anderson]

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "state_synced" over to the "flags"
field so modifications are safe.

Cc: Saravana Kannan <saravanak@kernel.org>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

(no changes since v4)

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 drivers/base/core.c    | 8 ++++----
 drivers/base/dd.c      | 8 +++-----
 include/linux/device.h | 9 +++++----
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index db5aec9e6a2b..e94749092345 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1123,7 +1123,7 @@ static void __device_links_queue_sync_state(struct device *dev,
 
 	if (!dev_has_sync_state(dev))
 		return;
-	if (dev->state_synced)
+	if (dev_state_synced(dev))
 		return;
 
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
@@ -1138,7 +1138,7 @@ static void __device_links_queue_sync_state(struct device *dev,
 	 * than once. This can happen if new consumers get added to the device
 	 * and probed before the list is flushed.
 	 */
-	dev->state_synced = true;
+	dev_set_state_synced(dev);
 
 	if (WARN_ON(!list_empty(&dev->links.defer_sync)))
 		return;
@@ -1779,7 +1779,7 @@ static int fw_devlink_dev_sync_state(struct device *dev, void *data)
 	struct device *sup = link->supplier;
 
 	if (!device_link_test(link, DL_FLAG_MANAGED) ||
-	    link->status == DL_STATE_ACTIVE || sup->state_synced ||
+	    link->status == DL_STATE_ACTIVE || dev_state_synced(sup) ||
 	    !dev_has_sync_state(sup))
 		return 0;
 
@@ -1793,7 +1793,7 @@ static int fw_devlink_dev_sync_state(struct device *dev, void *data)
 		return 0;
 
 	dev_warn(sup, "Timed out. Forcing sync_state()\n");
-	sup->state_synced = true;
+	dev_set_state_synced(sup);
 	get_device(sup);
 	list_add_tail(&sup->links.defer_sync, data);
 
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 70fa0b13e74f..067a06edd6bc 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -581,12 +581,10 @@ static ssize_t state_synced_store(struct device *dev,
 		return -EINVAL;
 
 	device_lock(dev);
-	if (!dev->state_synced) {
-		dev->state_synced = true;
+	if (!dev_test_and_set_state_synced(dev))
 		dev_sync_state(dev);
-	} else {
+	else
 		ret = -EINVAL;
-	}
 	device_unlock(dev);
 
 	return ret ? ret : count;
@@ -598,7 +596,7 @@ static ssize_t state_synced_show(struct device *dev,
 	bool val;
 
 	device_lock(dev);
-	val = dev->state_synced;
+	val = dev_state_synced(dev);
 	device_unlock(dev);
 
 	return sysfs_emit(buf, "%u\n", val);
diff --git a/include/linux/device.h b/include/linux/device.h
index 1c43ff695e83..b7a8b902efb3 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -478,6 +478,9 @@ struct device_physical_location {
  *		optional (if the coherent mask is large enough) also for dma
  *		allocations. This flag is managed by the dma ops instance from
  *		->dma_supported.
+ * @DEV_FLAG_STATE_SYNCED: The hardware state of this device has been synced to
+ *		match the software state of this device by calling the
+ *		driver/bus sync_state() callback.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
@@ -485,6 +488,7 @@ enum struct_device_flags {
 	DEV_FLAG_DMA_IOMMU = 2,
 	DEV_FLAG_DMA_SKIP_SYNC = 3,
 	DEV_FLAG_DMA_OPS_BYPASS = 4,
+	DEV_FLAG_STATE_SYNCED = 5,
 
 	DEV_FLAG_COUNT
 };
@@ -568,9 +572,6 @@ enum struct_device_flags {
  * @offline:	Set after successful invocation of bus type's .offline().
  * @of_node_reused: Set if the device-tree node is shared with an ancestor
  *              device.
- * @state_synced: The hardware state of this device has been synced to match
- *		  the software state of this device by calling the driver/bus
- *		  sync_state() callback.
  * @dma_coherent: this particular device is dma coherent, even if the
  *		architecture supports non-coherent devices.
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
@@ -680,7 +681,6 @@ struct device {
 	bool			offline_disabled:1;
 	bool			offline:1;
 	bool			of_node_reused:1;
-	bool			state_synced:1;
 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
@@ -717,6 +717,7 @@ __create_dev_flag_accessors(can_match, DEV_FLAG_CAN_MATCH);
 __create_dev_flag_accessors(dma_iommu, DEV_FLAG_DMA_IOMMU);
 __create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
 __create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
+__create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
 
 #undef __create_dev_flag_accessors
 
-- 
2.53.0.1213.gd9a14994de-goog

[PATCH v5 7/9] driver core: Replace dev->dma_coherent with dev_dma_coherent()

[Douglas Anderson]

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "dma_coherent" over to the "flags"
field so modifications are safe.

Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

NOTE: even though previously we only took up a bit if
CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE, CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU,
or CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL, in this change I reserve the
bit unconditionally.  While we could get the "dynamic" behavior by
changing the flags definition to be an unnumbered "enum", Greg has
requested that the numbers be stable.

(no changes since v4)

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 arch/arc/mm/dma.c                 |  4 ++--
 arch/arm/mach-highbank/highbank.c |  2 +-
 arch/arm/mach-mvebu/coherency.c   |  2 +-
 arch/arm/mm/dma-mapping-nommu.c   |  4 ++--
 arch/arm/mm/dma-mapping.c         | 28 ++++++++++++++--------------
 arch/arm64/mm/dma-mapping.c       |  2 +-
 arch/mips/mm/dma-noncoherent.c    |  2 +-
 arch/riscv/mm/dma-noncoherent.c   |  2 +-
 drivers/base/core.c               |  2 +-
 drivers/dma/ti/k3-udma-glue.c     |  6 +++---
 drivers/dma/ti/k3-udma.c          |  6 +++---
 include/linux/device.h            | 11 ++++-------
 include/linux/dma-map-ops.h       |  2 +-
 13 files changed, 35 insertions(+), 38 deletions(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 6b85e94f3275..9b9adb02b4c5 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -98,8 +98,8 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
 	 * DMA buffers.
 	 */
 	if (is_isa_arcv2() && ioc_enable && coherent)
-		dev->dma_coherent = true;
+		dev_set_dma_coherent(dev);
 
 	dev_info(dev, "use %scoherent DMA ops\n",
-		 dev->dma_coherent ? "" : "non");
+		 dev_dma_coherent(dev) ? "" : "non");
 }
diff --git a/arch/arm/mach-highbank/highbank.c b/arch/arm/mach-highbank/highbank.c
index 47335c7dadf8..8b7d0929dac4 100644
--- a/arch/arm/mach-highbank/highbank.c
+++ b/arch/arm/mach-highbank/highbank.c
@@ -98,7 +98,7 @@ static int highbank_platform_notifier(struct notifier_block *nb,
 	if (of_property_read_bool(dev->of_node, "dma-coherent")) {
 		val = readl(sregs_base + reg);
 		writel(val | 0xff01, sregs_base + reg);
-		dev->dma_coherent = true;
+		dev_set_dma_coherent(dev);
 	}
 
 	return NOTIFY_OK;
diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c
index fa2c1e1aeb96..7234d487ff39 100644
--- a/arch/arm/mach-mvebu/coherency.c
+++ b/arch/arm/mach-mvebu/coherency.c
@@ -95,7 +95,7 @@ static int mvebu_hwcc_notifier(struct notifier_block *nb,
 
 	if (event != BUS_NOTIFY_ADD_DEVICE)
 		return NOTIFY_DONE;
-	dev->dma_coherent = true;
+	dev_set_dma_coherent(dev);
 
 	return NOTIFY_OK;
 }
diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index fecac107fd0d..c6a70686507b 100644
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -42,11 +42,11 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
 		 * enough to check if MPU is in use or not since in absence of
 		 * MPU system memory map is used.
 		 */
-		dev->dma_coherent = cacheid ? coherent : true;
+		dev_assign_dma_coherent(dev, cacheid ? coherent : true);
 	} else {
 		/*
 		 * Assume coherent DMA in case MMU/MPU has not been set up.
 		 */
-		dev->dma_coherent = (get_cr() & CR_M) ? coherent : true;
+		dev_assign_dma_coherent(dev, (get_cr() & CR_M) ? coherent : true);
 	}
 }
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f304037d1c34..f9bc53b60f99 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1076,7 +1076,7 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
 	pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
 	struct page **pages;
 	void *addr = NULL;
-	int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+	int coherent_flag = dev_dma_coherent(dev) ? COHERENT : NORMAL;
 
 	*handle = DMA_MAPPING_ERROR;
 	size = PAGE_ALIGN(size);
@@ -1124,7 +1124,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 	if (vma->vm_pgoff >= nr_pages)
 		return -ENXIO;
 
-	if (!dev->dma_coherent)
+	if (!dev_dma_coherent(dev))
 		vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
 
 	err = vm_map_pages(vma, pages, nr_pages);
@@ -1141,7 +1141,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 static void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
 	dma_addr_t handle, unsigned long attrs)
 {
-	int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+	int coherent_flag = dev_dma_coherent(dev) ? COHERENT : NORMAL;
 	struct page **pages;
 	size = PAGE_ALIGN(size);
 
@@ -1202,7 +1202,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
 		phys_addr_t phys = page_to_phys(sg_page(s));
 		unsigned int len = PAGE_ALIGN(s->offset + s->length);
 
-		if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		if (!dev_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 			arch_sync_dma_for_device(sg_phys(s), s->length, dir);
 
 		prot = __dma_info_to_prot(dir, attrs);
@@ -1304,7 +1304,7 @@ static void arm_iommu_unmap_sg(struct device *dev,
 		if (sg_dma_len(s))
 			__iommu_remove_mapping(dev, sg_dma_address(s),
 					       sg_dma_len(s));
-		if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		if (!dev_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 			arch_sync_dma_for_cpu(sg_phys(s), s->length, dir);
 	}
 }
@@ -1323,7 +1323,7 @@ static void arm_iommu_sync_sg_for_cpu(struct device *dev,
 	struct scatterlist *s;
 	int i;
 
-	if (dev->dma_coherent)
+	if (dev_dma_coherent(dev))
 		return;
 
 	for_each_sg(sg, s, nents, i)
@@ -1345,7 +1345,7 @@ static void arm_iommu_sync_sg_for_device(struct device *dev,
 	struct scatterlist *s;
 	int i;
 
-	if (dev->dma_coherent)
+	if (dev_dma_coherent(dev))
 		return;
 
 	for_each_sg(sg, s, nents, i)
@@ -1371,7 +1371,7 @@ static dma_addr_t arm_iommu_map_phys(struct device *dev, phys_addr_t phys,
 	dma_addr_t dma_addr;
 	int ret, prot;
 
-	if (!dev->dma_coherent &&
+	if (!dev_dma_coherent(dev) &&
 	    !(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO)))
 		arch_sync_dma_for_device(phys, size, dir);
 
@@ -1412,7 +1412,7 @@ static void arm_iommu_unmap_phys(struct device *dev, dma_addr_t handle,
 	if (!iova)
 		return;
 
-	if (!dev->dma_coherent &&
+	if (!dev_dma_coherent(dev) &&
 	    !(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) {
 		phys_addr_t phys = iommu_iova_to_phys(mapping->domain, iova);
 
@@ -1431,7 +1431,7 @@ static void arm_iommu_sync_single_for_cpu(struct device *dev,
 	unsigned int offset = handle & ~PAGE_MASK;
 	phys_addr_t phys;
 
-	if (dev->dma_coherent || !iova)
+	if (dev_dma_coherent(dev) || !iova)
 		return;
 
 	phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1446,7 +1446,7 @@ static void arm_iommu_sync_single_for_device(struct device *dev,
 	unsigned int offset = handle & ~PAGE_MASK;
 	phys_addr_t phys;
 
-	if (dev->dma_coherent || !iova)
+	if (dev_dma_coherent(dev) || !iova)
 		return;
 
 	phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1701,13 +1701,13 @@ static void arm_teardown_iommu_dma_ops(struct device *dev) { }
 void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
 	/*
-	 * Due to legacy code that sets the ->dma_coherent flag from a bus
-	 * notifier we can't just assign coherent to the ->dma_coherent flag
+	 * Due to legacy code that sets the dma_coherent flag from a bus
+	 * notifier we can't just assign coherent to the dma_coherent flag
 	 * here, but instead have to make sure we only set but never clear it
 	 * for now.
 	 */
 	if (coherent)
-		dev->dma_coherent = true;
+		dev_set_dma_coherent(dev);
 
 	/*
 	 * Don't override the dma_ops if they have already been set. Ideally
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index b2b5792b2caa..dc1fce939451 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -48,7 +48,7 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
 		   dev_driver_string(dev), dev_name(dev),
 		   ARCH_DMA_MINALIGN, cls);
 
-	dev->dma_coherent = coherent;
+	dev_assign_dma_coherent(dev, coherent);
 
 	xen_setup_dma_ops(dev);
 }
diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c
index ab4f2a75a7d0..30ef3e247eb7 100644
--- a/arch/mips/mm/dma-noncoherent.c
+++ b/arch/mips/mm/dma-noncoherent.c
@@ -139,6 +139,6 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 #ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS
 void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
-	dev->dma_coherent = coherent;
+	dev_assign_dma_coherent(dev, coherent);
 }
 #endif
diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
index cb89d7e0ba88..a1ec2d71d1c9 100644
--- a/arch/riscv/mm/dma-noncoherent.c
+++ b/arch/riscv/mm/dma-noncoherent.c
@@ -140,7 +140,7 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
 		   "%s %s: device non-coherent but no non-coherent operations supported",
 		   dev_driver_string(dev), dev_name(dev));
 
-	dev->dma_coherent = coherent;
+	dev_assign_dma_coherent(dev, coherent);
 }
 
 void riscv_noncoherent_supported(void)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index e94749092345..8a83d7c93361 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3173,7 +3173,7 @@ void device_initialize(struct device *dev)
 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
-	dev->dma_coherent = dma_default_coherent;
+	dev_assign_dma_coherent(dev, dma_default_coherent);
 #endif
 	swiotlb_dev_init(dev);
 }
diff --git a/drivers/dma/ti/k3-udma-glue.c b/drivers/dma/ti/k3-udma-glue.c
index f87d244cc2d6..686dc140293e 100644
--- a/drivers/dma/ti/k3-udma-glue.c
+++ b/drivers/dma/ti/k3-udma-glue.c
@@ -312,7 +312,7 @@ k3_udma_glue_request_tx_chn_common(struct device *dev,
 
 	if (xudma_is_pktdma(tx_chn->common.udmax)) {
 		/* prepare the channel device as coherent */
-		tx_chn->common.chan_dev.dma_coherent = true;
+		dev_set_dma_coherent(&tx_chn->common.chan_dev);
 		dma_coerce_mask_and_coherent(&tx_chn->common.chan_dev,
 					     DMA_BIT_MASK(48));
 	}
@@ -1003,7 +1003,7 @@ k3_udma_glue_request_rx_chn_priv(struct device *dev, const char *name,
 
 	if (xudma_is_pktdma(rx_chn->common.udmax)) {
 		/* prepare the channel device as coherent */
-		rx_chn->common.chan_dev.dma_coherent = true;
+		dev_set_dma_coherent(&rx_chn->common.chan_dev);
 		dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,
 					     DMA_BIT_MASK(48));
 	}
@@ -1104,7 +1104,7 @@ k3_udma_glue_request_remote_rx_chn_common(struct k3_udma_glue_rx_channel *rx_chn
 
 	if (xudma_is_pktdma(rx_chn->common.udmax)) {
 		/* prepare the channel device as coherent */
-		rx_chn->common.chan_dev.dma_coherent = true;
+		dev_set_dma_coherent(&rx_chn->common.chan_dev);
 		dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,
 					     DMA_BIT_MASK(48));
 		rx_chn->single_fdq = false;
diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index c964ebfcf3b6..1cf158eb7bdb 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -428,18 +428,18 @@ static void k3_configure_chan_coherency(struct dma_chan *chan, u32 asel)
 		/* No special handling for the channel */
 		chan->dev->chan_dma_dev = false;
 
-		chan_dev->dma_coherent = false;
+		dev_clear_dma_coherent(chan_dev);
 		chan_dev->dma_parms = NULL;
 	} else if (asel == 14 || asel == 15) {
 		chan->dev->chan_dma_dev = true;
 
-		chan_dev->dma_coherent = true;
+		dev_set_dma_coherent(chan_dev);
 		dma_coerce_mask_and_coherent(chan_dev, DMA_BIT_MASK(48));
 		chan_dev->dma_parms = chan_dev->parent->dma_parms;
 	} else {
 		dev_warn(chan->device->dev, "Invalid ASEL value: %u\n", asel);
 
-		chan_dev->dma_coherent = false;
+		dev_clear_dma_coherent(chan_dev);
 		chan_dev->dma_parms = NULL;
 	}
 }
diff --git a/include/linux/device.h b/include/linux/device.h
index b7a8b902efb3..5b0fb6ad4c72 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -481,6 +481,8 @@ struct device_physical_location {
  * @DEV_FLAG_STATE_SYNCED: The hardware state of this device has been synced to
  *		match the software state of this device by calling the
  *		driver/bus sync_state() callback.
+ * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
+ *		architecture supports non-coherent devices.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
@@ -489,6 +491,7 @@ enum struct_device_flags {
 	DEV_FLAG_DMA_SKIP_SYNC = 3,
 	DEV_FLAG_DMA_OPS_BYPASS = 4,
 	DEV_FLAG_STATE_SYNCED = 5,
+	DEV_FLAG_DMA_COHERENT = 6,
 
 	DEV_FLAG_COUNT
 };
@@ -572,8 +575,6 @@ enum struct_device_flags {
  * @offline:	Set after successful invocation of bus type's .offline().
  * @of_node_reused: Set if the device-tree node is shared with an ancestor
  *              device.
- * @dma_coherent: this particular device is dma coherent, even if the
- *		architecture supports non-coherent devices.
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
@@ -681,11 +682,6 @@ struct device {
 	bool			offline_disabled:1;
 	bool			offline:1;
 	bool			of_node_reused:1;
-#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
-    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
-    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
-	bool			dma_coherent:1;
-#endif
 
 	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
 };
@@ -718,6 +714,7 @@ __create_dev_flag_accessors(dma_iommu, DEV_FLAG_DMA_IOMMU);
 __create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
 __create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
 __create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
+__create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
 
 #undef __create_dev_flag_accessors
 
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index edd7de60a957..44dd9035b4fe 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -230,7 +230,7 @@ int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
 extern bool dma_default_coherent;
 static inline bool dev_is_dma_coherent(struct device *dev)
 {
-	return dev->dma_coherent;
+	return dev_dma_coherent(dev);
 }
 #else
 #define dma_default_coherent true
-- 
2.53.0.1213.gd9a14994de-goog

[PATCH v5 8/9] driver core: Replace dev->of_node_reused with dev_of_node_reused()

[Douglas Anderson]

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "of_node_reused" over to the "flags"
field so modifications are safe.

Cc: Johan Hovold <johan@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

(no changes since v4)

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 drivers/base/core.c                      | 2 +-
 drivers/base/pinctrl.c                   | 2 +-
 drivers/base/platform.c                  | 2 +-
 drivers/net/pcs/pcs-xpcs-plat.c          | 2 +-
 drivers/of/device.c                      | 6 +++---
 drivers/pci/of.c                         | 2 +-
 drivers/pci/pwrctrl/core.c               | 2 +-
 drivers/regulator/bq257xx-regulator.c    | 2 +-
 drivers/regulator/rk808-regulator.c      | 2 +-
 drivers/tty/serial/serial_base_bus.c     | 2 +-
 drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
 include/linux/device.h                   | 7 ++++---
 12 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 8a83d7c93361..30825bf83234 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -5283,7 +5283,7 @@ void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
 {
 	of_node_put(dev->of_node);
 	dev->of_node = of_node_get(dev2->of_node);
-	dev->of_node_reused = true;
+	dev_set_of_node_reused(dev);
 }
 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
 
diff --git a/drivers/base/pinctrl.c b/drivers/base/pinctrl.c
index 6e250272c843..0bbc83231234 100644
--- a/drivers/base/pinctrl.c
+++ b/drivers/base/pinctrl.c
@@ -24,7 +24,7 @@ int pinctrl_bind_pins(struct device *dev)
 {
 	int ret;
 
-	if (dev->of_node_reused)
+	if (dev_of_node_reused(dev))
 		return 0;
 
 	dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index d44591d52e36..199e6fb25770 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -856,7 +856,7 @@ struct platform_device *platform_device_register_full(
 	pdev->dev.parent = pdevinfo->parent;
 	pdev->dev.fwnode = pdevinfo->fwnode;
 	pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode));
-	pdev->dev.of_node_reused = pdevinfo->of_node_reused;
+	dev_assign_of_node_reused(&pdev->dev, pdevinfo->of_node_reused);
 
 	if (pdevinfo->dma_mask) {
 		pdev->platform_dma_mask = pdevinfo->dma_mask;
diff --git a/drivers/net/pcs/pcs-xpcs-plat.c b/drivers/net/pcs/pcs-xpcs-plat.c
index b8c48f9effbf..f4b1b8246ce9 100644
--- a/drivers/net/pcs/pcs-xpcs-plat.c
+++ b/drivers/net/pcs/pcs-xpcs-plat.c
@@ -349,7 +349,7 @@ static int xpcs_plat_init_dev(struct dw_xpcs_plat *pxpcs)
 	 * up later. Make sure DD-core is aware of the OF-node being re-used.
 	 */
 	device_set_node(&mdiodev->dev, fwnode_handle_get(dev_fwnode(dev)));
-	mdiodev->dev.of_node_reused = true;
+	dev_set_of_node_reused(&mdiodev->dev);
 
 	/* Pass the data further so the DW XPCS driver core could use it */
 	mdiodev->dev.platform_data = (void *)device_get_match_data(dev);
diff --git a/drivers/of/device.c b/drivers/of/device.c
index f7e75e527667..be4e1584e0af 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -26,7 +26,7 @@
 const struct of_device_id *of_match_device(const struct of_device_id *matches,
 					   const struct device *dev)
 {
-	if (!matches || !dev->of_node || dev->of_node_reused)
+	if (!matches || !dev->of_node || dev_of_node_reused(dev))
 		return NULL;
 	return of_match_node(matches, dev->of_node);
 }
@@ -192,7 +192,7 @@ ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
 {
 	ssize_t sl;
 
-	if (!dev || !dev->of_node || dev->of_node_reused)
+	if (!dev || !dev->of_node || dev_of_node_reused(dev))
 		return -ENODEV;
 
 	sl = of_modalias(dev->of_node, str, len - 2);
@@ -254,7 +254,7 @@ int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *
 {
 	int sl;
 
-	if ((!dev) || (!dev->of_node) || dev->of_node_reused)
+	if ((!dev) || (!dev->of_node) || dev_of_node_reused(dev))
 		return -ENODEV;
 
 	/* Devicetree modalias is tricky, we add it in 2 steps */
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 9f8eb5df279e..1f9b669abdb0 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -38,7 +38,7 @@ int pci_set_of_node(struct pci_dev *dev)
 	struct device *pdev __free(put_device) =
 		bus_find_device_by_of_node(&platform_bus_type, node);
 	if (pdev)
-		dev->bus->dev.of_node_reused = true;
+		dev_set_of_node_reused(&dev->bus->dev);
 
 	device_set_node(&dev->dev, of_fwnode_handle(no_free_ptr(node)));
 	return 0;
diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
index 7754baed67f2..72963a92362a 100644
--- a/drivers/pci/pwrctrl/core.c
+++ b/drivers/pci/pwrctrl/core.c
@@ -39,7 +39,7 @@ static int pci_pwrctrl_notify(struct notifier_block *nb, unsigned long action,
 		 * If we got here then the PCI device is the second after the
 		 * power control platform device. Mark its OF node as reused.
 		 */
-		dev->of_node_reused = true;
+		dev_set_of_node_reused(dev);
 		break;
 	}
 
diff --git a/drivers/regulator/bq257xx-regulator.c b/drivers/regulator/bq257xx-regulator.c
index dab8f1ab4450..40e0f1a7ae81 100644
--- a/drivers/regulator/bq257xx-regulator.c
+++ b/drivers/regulator/bq257xx-regulator.c
@@ -143,7 +143,7 @@ static int bq257xx_regulator_probe(struct platform_device *pdev)
 	struct regulator_config cfg = {};
 
 	pdev->dev.of_node = pdev->dev.parent->of_node;
-	pdev->dev.of_node_reused = true;
+	dev_set_of_node_reused(&pdev->dev);
 
 	pdata = devm_kzalloc(&pdev->dev, sizeof(struct bq257xx_reg_data), GFP_KERNEL);
 	if (!pdata)
diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c
index e66408f23bb6..8297d31cde9f 100644
--- a/drivers/regulator/rk808-regulator.c
+++ b/drivers/regulator/rk808-regulator.c
@@ -2115,7 +2115,7 @@ static int rk808_regulator_probe(struct platform_device *pdev)
 	int ret, i, nregulators;
 
 	pdev->dev.of_node = pdev->dev.parent->of_node;
-	pdev->dev.of_node_reused = true;
+	dev_set_of_node_reused(&pdev->dev);
 
 	regmap = dev_get_regmap(pdev->dev.parent, NULL);
 	if (!regmap)
diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
index a12935f6b992..5f23284a8778 100644
--- a/drivers/tty/serial/serial_base_bus.c
+++ b/drivers/tty/serial/serial_base_bus.c
@@ -74,7 +74,7 @@ static int serial_base_device_init(struct uart_port *port,
 	dev->parent = parent_dev;
 	dev->bus = &serial_base_bus_type;
 	dev->release = release;
-	dev->of_node_reused = true;
+	dev_set_of_node_reused(dev);
 
 	device_set_node(dev, fwnode_handle_get(dev_fwnode(parent_dev)));
 
diff --git a/drivers/usb/gadget/udc/aspeed-vhub/dev.c b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
index 2ecd049dacc2..8b9449d16324 100644
--- a/drivers/usb/gadget/udc/aspeed-vhub/dev.c
+++ b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
@@ -593,7 +593,7 @@ int ast_vhub_init_dev(struct ast_vhub *vhub, unsigned int idx)
 		d->gadget.max_speed = USB_SPEED_HIGH;
 	d->gadget.speed = USB_SPEED_UNKNOWN;
 	d->gadget.dev.of_node = vhub->pdev->dev.of_node;
-	d->gadget.dev.of_node_reused = true;
+	dev_set_of_node_reused(&d->gadget.dev);
 
 	rc = usb_add_gadget_udc(d->port_dev, &d->gadget);
 	if (rc != 0)
diff --git a/include/linux/device.h b/include/linux/device.h
index 5b0fb6ad4c72..a79865a212e9 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -483,6 +483,8 @@ struct device_physical_location {
  *		driver/bus sync_state() callback.
  * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
  *		architecture supports non-coherent devices.
+ * @DEV_FLAG_OF_NODE_REUSED: Set if the device-tree node is shared with an
+ *		ancestor device.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
@@ -492,6 +494,7 @@ enum struct_device_flags {
 	DEV_FLAG_DMA_OPS_BYPASS = 4,
 	DEV_FLAG_STATE_SYNCED = 5,
 	DEV_FLAG_DMA_COHERENT = 6,
+	DEV_FLAG_OF_NODE_REUSED = 7,
 
 	DEV_FLAG_COUNT
 };
@@ -573,8 +576,6 @@ enum struct_device_flags {
  *
  * @offline_disabled: If set, the device is permanently online.
  * @offline:	Set after successful invocation of bus type's .offline().
- * @of_node_reused: Set if the device-tree node is shared with an ancestor
- *              device.
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
@@ -681,7 +682,6 @@ struct device {
 
 	bool			offline_disabled:1;
 	bool			offline:1;
-	bool			of_node_reused:1;
 
 	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
 };
@@ -715,6 +715,7 @@ __create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
 __create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
 __create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
 __create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
+__create_dev_flag_accessors(of_node_reused, DEV_FLAG_OF_NODE_REUSED);
 
 #undef __create_dev_flag_accessors
 
-- 
2.53.0.1213.gd9a14994de-goog

Re: [PATCH v5 8/9] driver core: Replace dev->of_node_reused with dev_of_node_reused()

[Manivannan Sadhasivam]

On Mon, Apr 06, 2026 at 04:23:01PM -0700, Douglas Anderson wrote:
> In C, bitfields are not necessarily safe to modify from multiple
> threads without locking. Switch "of_node_reused" over to the "flags"
> field so modifications are safe.
> 
> Cc: Johan Hovold <johan@kernel.org>
> Acked-by: Mark Brown <broonie@kernel.org>
> Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
> Reviewed-by: Danilo Krummrich <dakr@kernel.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>

Acked-by: Manivannan Sadhasivam <mani@kernel.org> # PCI_PWRCTRL

- Mani

> ---
> Not fixing any known bugs; problem is theoretical and found by code
> inspection. Change is done somewhat manually and only lightly tested
> (mostly compile-time tested).
> 
> (no changes since v4)
> 
> Changes in v4:
> - Use accessor functions for flags
> 
> Changes in v3:
> - New
> 
>  drivers/base/core.c                      | 2 +-
>  drivers/base/pinctrl.c                   | 2 +-
>  drivers/base/platform.c                  | 2 +-
>  drivers/net/pcs/pcs-xpcs-plat.c          | 2 +-
>  drivers/of/device.c                      | 6 +++---
>  drivers/pci/of.c                         | 2 +-
>  drivers/pci/pwrctrl/core.c               | 2 +-
>  drivers/regulator/bq257xx-regulator.c    | 2 +-
>  drivers/regulator/rk808-regulator.c      | 2 +-
>  drivers/tty/serial/serial_base_bus.c     | 2 +-
>  drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
>  include/linux/device.h                   | 7 ++++---
>  12 files changed, 17 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 8a83d7c93361..30825bf83234 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -5283,7 +5283,7 @@ void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
>  {
>  	of_node_put(dev->of_node);
>  	dev->of_node = of_node_get(dev2->of_node);
> -	dev->of_node_reused = true;
> +	dev_set_of_node_reused(dev);
>  }
>  EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
>  
> diff --git a/drivers/base/pinctrl.c b/drivers/base/pinctrl.c
> index 6e250272c843..0bbc83231234 100644
> --- a/drivers/base/pinctrl.c
> +++ b/drivers/base/pinctrl.c
> @@ -24,7 +24,7 @@ int pinctrl_bind_pins(struct device *dev)
>  {
>  	int ret;
>  
> -	if (dev->of_node_reused)
> +	if (dev_of_node_reused(dev))
>  		return 0;
>  
>  	dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index d44591d52e36..199e6fb25770 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -856,7 +856,7 @@ struct platform_device *platform_device_register_full(
>  	pdev->dev.parent = pdevinfo->parent;
>  	pdev->dev.fwnode = pdevinfo->fwnode;
>  	pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode));
> -	pdev->dev.of_node_reused = pdevinfo->of_node_reused;
> +	dev_assign_of_node_reused(&pdev->dev, pdevinfo->of_node_reused);
>  
>  	if (pdevinfo->dma_mask) {
>  		pdev->platform_dma_mask = pdevinfo->dma_mask;
> diff --git a/drivers/net/pcs/pcs-xpcs-plat.c b/drivers/net/pcs/pcs-xpcs-plat.c
> index b8c48f9effbf..f4b1b8246ce9 100644
> --- a/drivers/net/pcs/pcs-xpcs-plat.c
> +++ b/drivers/net/pcs/pcs-xpcs-plat.c
> @@ -349,7 +349,7 @@ static int xpcs_plat_init_dev(struct dw_xpcs_plat *pxpcs)
>  	 * up later. Make sure DD-core is aware of the OF-node being re-used.
>  	 */
>  	device_set_node(&mdiodev->dev, fwnode_handle_get(dev_fwnode(dev)));
> -	mdiodev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&mdiodev->dev);
>  
>  	/* Pass the data further so the DW XPCS driver core could use it */
>  	mdiodev->dev.platform_data = (void *)device_get_match_data(dev);
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index f7e75e527667..be4e1584e0af 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -26,7 +26,7 @@
>  const struct of_device_id *of_match_device(const struct of_device_id *matches,
>  					   const struct device *dev)
>  {
> -	if (!matches || !dev->of_node || dev->of_node_reused)
> +	if (!matches || !dev->of_node || dev_of_node_reused(dev))
>  		return NULL;
>  	return of_match_node(matches, dev->of_node);
>  }
> @@ -192,7 +192,7 @@ ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
>  {
>  	ssize_t sl;
>  
> -	if (!dev || !dev->of_node || dev->of_node_reused)
> +	if (!dev || !dev->of_node || dev_of_node_reused(dev))
>  		return -ENODEV;
>  
>  	sl = of_modalias(dev->of_node, str, len - 2);
> @@ -254,7 +254,7 @@ int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *
>  {
>  	int sl;
>  
> -	if ((!dev) || (!dev->of_node) || dev->of_node_reused)
> +	if ((!dev) || (!dev->of_node) || dev_of_node_reused(dev))
>  		return -ENODEV;
>  
>  	/* Devicetree modalias is tricky, we add it in 2 steps */
> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> index 9f8eb5df279e..1f9b669abdb0 100644
> --- a/drivers/pci/of.c
> +++ b/drivers/pci/of.c
> @@ -38,7 +38,7 @@ int pci_set_of_node(struct pci_dev *dev)
>  	struct device *pdev __free(put_device) =
>  		bus_find_device_by_of_node(&platform_bus_type, node);
>  	if (pdev)
> -		dev->bus->dev.of_node_reused = true;
> +		dev_set_of_node_reused(&dev->bus->dev);
>  
>  	device_set_node(&dev->dev, of_fwnode_handle(no_free_ptr(node)));
>  	return 0;
> diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
> index 7754baed67f2..72963a92362a 100644
> --- a/drivers/pci/pwrctrl/core.c
> +++ b/drivers/pci/pwrctrl/core.c
> @@ -39,7 +39,7 @@ static int pci_pwrctrl_notify(struct notifier_block *nb, unsigned long action,
>  		 * If we got here then the PCI device is the second after the
>  		 * power control platform device. Mark its OF node as reused.
>  		 */
> -		dev->of_node_reused = true;
> +		dev_set_of_node_reused(dev);
>  		break;
>  	}
>  
> diff --git a/drivers/regulator/bq257xx-regulator.c b/drivers/regulator/bq257xx-regulator.c
> index dab8f1ab4450..40e0f1a7ae81 100644
> --- a/drivers/regulator/bq257xx-regulator.c
> +++ b/drivers/regulator/bq257xx-regulator.c
> @@ -143,7 +143,7 @@ static int bq257xx_regulator_probe(struct platform_device *pdev)
>  	struct regulator_config cfg = {};
>  
>  	pdev->dev.of_node = pdev->dev.parent->of_node;
> -	pdev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&pdev->dev);
>  
>  	pdata = devm_kzalloc(&pdev->dev, sizeof(struct bq257xx_reg_data), GFP_KERNEL);
>  	if (!pdata)
> diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c
> index e66408f23bb6..8297d31cde9f 100644
> --- a/drivers/regulator/rk808-regulator.c
> +++ b/drivers/regulator/rk808-regulator.c
> @@ -2115,7 +2115,7 @@ static int rk808_regulator_probe(struct platform_device *pdev)
>  	int ret, i, nregulators;
>  
>  	pdev->dev.of_node = pdev->dev.parent->of_node;
> -	pdev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&pdev->dev);
>  
>  	regmap = dev_get_regmap(pdev->dev.parent, NULL);
>  	if (!regmap)
> diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
> index a12935f6b992..5f23284a8778 100644
> --- a/drivers/tty/serial/serial_base_bus.c
> +++ b/drivers/tty/serial/serial_base_bus.c
> @@ -74,7 +74,7 @@ static int serial_base_device_init(struct uart_port *port,
>  	dev->parent = parent_dev;
>  	dev->bus = &serial_base_bus_type;
>  	dev->release = release;
> -	dev->of_node_reused = true;
> +	dev_set_of_node_reused(dev);
>  
>  	device_set_node(dev, fwnode_handle_get(dev_fwnode(parent_dev)));
>  
> diff --git a/drivers/usb/gadget/udc/aspeed-vhub/dev.c b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
> index 2ecd049dacc2..8b9449d16324 100644
> --- a/drivers/usb/gadget/udc/aspeed-vhub/dev.c
> +++ b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
> @@ -593,7 +593,7 @@ int ast_vhub_init_dev(struct ast_vhub *vhub, unsigned int idx)
>  		d->gadget.max_speed = USB_SPEED_HIGH;
>  	d->gadget.speed = USB_SPEED_UNKNOWN;
>  	d->gadget.dev.of_node = vhub->pdev->dev.of_node;
> -	d->gadget.dev.of_node_reused = true;
> +	dev_set_of_node_reused(&d->gadget.dev);
>  
>  	rc = usb_add_gadget_udc(d->port_dev, &d->gadget);
>  	if (rc != 0)
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 5b0fb6ad4c72..a79865a212e9 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -483,6 +483,8 @@ struct device_physical_location {
>   *		driver/bus sync_state() callback.
>   * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
>   *		architecture supports non-coherent devices.
> + * @DEV_FLAG_OF_NODE_REUSED: Set if the device-tree node is shared with an
> + *		ancestor device.
>   */
>  enum struct_device_flags {
>  	DEV_FLAG_READY_TO_PROBE = 0,
> @@ -492,6 +494,7 @@ enum struct_device_flags {
>  	DEV_FLAG_DMA_OPS_BYPASS = 4,
>  	DEV_FLAG_STATE_SYNCED = 5,
>  	DEV_FLAG_DMA_COHERENT = 6,
> +	DEV_FLAG_OF_NODE_REUSED = 7,
>  
>  	DEV_FLAG_COUNT
>  };
> @@ -573,8 +576,6 @@ enum struct_device_flags {
>   *
>   * @offline_disabled: If set, the device is permanently online.
>   * @offline:	Set after successful invocation of bus type's .offline().
> - * @of_node_reused: Set if the device-tree node is shared with an ancestor
> - *              device.
>   * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
>   *
>   * At the lowest level, every device in a Linux system is represented by an
> @@ -681,7 +682,6 @@ struct device {
>  
>  	bool			offline_disabled:1;
>  	bool			offline:1;
> -	bool			of_node_reused:1;
>  
>  	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
>  };
> @@ -715,6 +715,7 @@ __create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
>  __create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
>  __create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
>  __create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
> +__create_dev_flag_accessors(of_node_reused, DEV_FLAG_OF_NODE_REUSED);
>  
>  #undef __create_dev_flag_accessors
>  
> -- 
> 2.53.0.1213.gd9a14994de-goog
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v5 8/9] driver core: Replace dev->of_node_reused with dev_of_node_reused()

[Johan Hovold]

On Mon, Apr 06, 2026 at 04:23:01PM -0700, Doug Anderson wrote:
> In C, bitfields are not necessarily safe to modify from multiple
> threads without locking. Switch "of_node_reused" over to the "flags"
> field so modifications are safe.

This flag is only set before registering a device with driver core so
there is no issue using the existing bitfield here (with the caveat that
PCI pwrctrl may have gotten that wrong). I haven't checked the other
flags, but I assume most of them work the same way.

But apart from the commit message being misleading, switching to using
atomic ops and accessors for consistency is fine.

> Cc: Johan Hovold <johan@kernel.org>
> Acked-by: Mark Brown <broonie@kernel.org>
> Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
> Reviewed-by: Danilo Krummrich <dakr@kernel.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
> Not fixing any known bugs; problem is theoretical and found by code
> inspection. Change is done somewhat manually and only lightly tested
> (mostly compile-time tested).
 
> diff --git a/drivers/regulator/bq257xx-regulator.c b/drivers/regulator/bq257xx-regulator.c
> index dab8f1ab4450..40e0f1a7ae81 100644
> --- a/drivers/regulator/bq257xx-regulator.c
> +++ b/drivers/regulator/bq257xx-regulator.c
> @@ -143,7 +143,7 @@ static int bq257xx_regulator_probe(struct platform_device *pdev)
>  	struct regulator_config cfg = {};
>  
>  	pdev->dev.of_node = pdev->dev.parent->of_node;
> -	pdev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&pdev->dev);
>  
>  	pdata = devm_kzalloc(&pdev->dev, sizeof(struct bq257xx_reg_data), GFP_KERNEL);
>  	if (!pdata)
> diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c
> index e66408f23bb6..8297d31cde9f 100644
> --- a/drivers/regulator/rk808-regulator.c
> +++ b/drivers/regulator/rk808-regulator.c
> @@ -2115,7 +2115,7 @@ static int rk808_regulator_probe(struct platform_device *pdev)
>  	int ret, i, nregulators;
>  
>  	pdev->dev.of_node = pdev->dev.parent->of_node;
> -	pdev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&pdev->dev);
>  
>  	regmap = dev_get_regmap(pdev->dev.parent, NULL);
>  	if (!regmap)

These two uses are broken currently though and should be using
device_set_of_node_from_dev() so that an extra reference is taken to
balance the one dropped by the platform bus code.

I'll send two fixes to Mark, any merge conflict should be trivial to
fixup.

Reviewed-by: Johan Hovold <johan@kernel.org>

Johan

Re: [PATCH v5 8/9] driver core: Replace dev->of_node_reused with dev_of_node_reused()

[Rob Herring (Arm)]

On Mon, 06 Apr 2026 16:23:01 -0700, Douglas Anderson wrote:
> In C, bitfields are not necessarily safe to modify from multiple
> threads without locking. Switch "of_node_reused" over to the "flags"
> field so modifications are safe.
> 
> Cc: Johan Hovold <johan@kernel.org>
> Acked-by: Mark Brown <broonie@kernel.org>
> Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
> Reviewed-by: Danilo Krummrich <dakr@kernel.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
> Not fixing any known bugs; problem is theoretical and found by code
> inspection. Change is done somewhat manually and only lightly tested
> (mostly compile-time tested).
> 
> (no changes since v4)
> 
> Changes in v4:
> - Use accessor functions for flags
> 
> Changes in v3:
> - New
> 
>  drivers/base/core.c                      | 2 +-
>  drivers/base/pinctrl.c                   | 2 +-
>  drivers/base/platform.c                  | 2 +-
>  drivers/net/pcs/pcs-xpcs-plat.c          | 2 +-
>  drivers/of/device.c                      | 6 +++---
>  drivers/pci/of.c                         | 2 +-
>  drivers/pci/pwrctrl/core.c               | 2 +-
>  drivers/regulator/bq257xx-regulator.c    | 2 +-
>  drivers/regulator/rk808-regulator.c      | 2 +-
>  drivers/tty/serial/serial_base_bus.c     | 2 +-
>  drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
>  include/linux/device.h                   | 7 ++++---
>  12 files changed, 17 insertions(+), 16 deletions(-)
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

[PATCH v5 9/9] driver core: Replace dev->offline + ->offline_disabled with accessors

[Douglas Anderson]

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "offline" and "offline_disabled" over
to the "flags" field so modifications are safe.

Cc: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

(no changes since v4)

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 arch/arm64/kernel/cpufeature.c                 |  2 +-
 .../powerpc/platforms/pseries/hotplug-memory.c |  4 ++--
 drivers/acpi/scan.c                            |  2 +-
 drivers/base/core.c                            | 18 +++++++++---------
 drivers/base/cpu.c                             |  4 ++--
 drivers/base/memory.c                          |  2 +-
 include/linux/device.h                         | 12 ++++++------
 kernel/cpu.c                                   |  4 ++--
 8 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 32c2dbcc0c64..c832aa565dc2 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -4042,7 +4042,7 @@ static int enable_mismatched_32bit_el0(unsigned int cpu)
 	 */
 	lucky_winner = cpu_32bit ? cpu : cpumask_any_and(cpu_32bit_el0_mask,
 							 cpu_active_mask);
-	get_cpu_device(lucky_winner)->offline_disabled = true;
+	dev_set_offline_disabled(get_cpu_device(lucky_winner));
 	setup_elf_hwcaps(compat_elf_hwcaps);
 	elf_hwcap_fixup();
 	pr_info("Asymmetric 32-bit EL0 support detected on CPU %u; CPU hot-unplug disabled on CPU %u\n",
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index b2f14db59034..75f85a5da981 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -213,9 +213,9 @@ static int dlpar_change_lmb_state(struct drmem_lmb *lmb, bool online)
 		return -EINVAL;
 	}
 
-	if (online && mem_block->dev.offline)
+	if (online && dev_offline(&mem_block->dev))
 		rc = device_online(&mem_block->dev);
-	else if (!online && !mem_block->dev.offline)
+	else if (!online && !dev_offline(&mem_block->dev))
 		rc = device_offline(&mem_block->dev);
 	else
 		rc = 0;
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index e8cdbdb46fdb..1353adbcc234 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -122,7 +122,7 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent)
 	mutex_lock_nested(&adev->physical_node_lock, SINGLE_DEPTH_NESTING);
 
 	list_for_each_entry(pn, &adev->physical_node_list, node)
-		if (device_supports_offline(pn->dev) && !pn->dev->offline) {
+		if (device_supports_offline(pn->dev) && !dev_offline(pn->dev)) {
 			if (uevent)
 				kobject_uevent_env(&pn->dev->kobj, KOBJ_CHANGE, envp);
 
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 30825bf83234..4f293aed879a 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2788,7 +2788,7 @@ static ssize_t online_show(struct device *dev, struct device_attribute *attr,
 	bool val;
 
 	device_lock(dev);
-	val = !dev->offline;
+	val = !dev_offline(dev);
 	device_unlock(dev);
 	return sysfs_emit(buf, "%u\n", val);
 }
@@ -2913,7 +2913,7 @@ static int device_add_attrs(struct device *dev)
 	if (error)
 		goto err_remove_type_groups;
 
-	if (device_supports_offline(dev) && !dev->offline_disabled) {
+	if (device_supports_offline(dev) && !dev_offline_disabled(dev)) {
 		error = device_create_file(dev, &dev_attr_online);
 		if (error)
 			goto err_remove_dev_groups;
@@ -4180,7 +4180,7 @@ static int device_check_offline(struct device *dev, void *not_used)
 	if (ret)
 		return ret;
 
-	return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
+	return device_supports_offline(dev) && !dev_offline(dev) ? -EBUSY : 0;
 }
 
 /**
@@ -4198,7 +4198,7 @@ int device_offline(struct device *dev)
 {
 	int ret;
 
-	if (dev->offline_disabled)
+	if (dev_offline_disabled(dev))
 		return -EPERM;
 
 	ret = device_for_each_child(dev, NULL, device_check_offline);
@@ -4207,13 +4207,13 @@ int device_offline(struct device *dev)
 
 	device_lock(dev);
 	if (device_supports_offline(dev)) {
-		if (dev->offline) {
+		if (dev_offline(dev)) {
 			ret = 1;
 		} else {
 			ret = dev->bus->offline(dev);
 			if (!ret) {
 				kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
-				dev->offline = true;
+				dev_set_offline(dev);
 			}
 		}
 	}
@@ -4238,11 +4238,11 @@ int device_online(struct device *dev)
 
 	device_lock(dev);
 	if (device_supports_offline(dev)) {
-		if (dev->offline) {
+		if (dev_offline(dev)) {
 			ret = dev->bus->online(dev);
 			if (!ret) {
 				kobject_uevent(&dev->kobj, KOBJ_ONLINE);
-				dev->offline = false;
+				dev_clear_offline(dev);
 			}
 		} else {
 			ret = 1;
@@ -4716,7 +4716,7 @@ static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
 	if (error)
 		return error;
 
-	if (device_supports_offline(dev) && !dev->offline_disabled) {
+	if (device_supports_offline(dev) && !dev_offline_disabled(dev)) {
 		/* Change online device attributes of @dev to @kuid/@kgid. */
 		error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
 						kuid, kgid);
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 875abdc9942e..19d288a3c80c 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -422,8 +422,8 @@ int register_cpu(struct cpu *cpu, int num)
 	cpu->dev.id = num;
 	cpu->dev.bus = &cpu_subsys;
 	cpu->dev.release = cpu_device_release;
-	cpu->dev.offline_disabled = !cpu->hotpluggable;
-	cpu->dev.offline = !cpu_online(num);
+	dev_assign_offline_disabled(&cpu->dev, !cpu->hotpluggable);
+	dev_assign_offline(&cpu->dev, !cpu_online(num));
 	cpu->dev.of_node = of_get_cpu_node(num, NULL);
 	cpu->dev.groups = common_cpu_attr_groups;
 	if (cpu->hotpluggable)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index a3091924918b..5005654f44fa 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -697,7 +697,7 @@ static int __add_memory_block(struct memory_block *memory)
 	memory->dev.id = memory->start_section_nr / sections_per_block;
 	memory->dev.release = memory_block_release;
 	memory->dev.groups = memory_memblk_attr_groups;
-	memory->dev.offline = memory->state == MEM_OFFLINE;
+	dev_assign_offline(&memory->dev, memory->state == MEM_OFFLINE);
 
 	ret = device_register(&memory->dev);
 	if (ret) {
diff --git a/include/linux/device.h b/include/linux/device.h
index a79865a212e9..d695f7537112 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -485,6 +485,8 @@ struct device_physical_location {
  *		architecture supports non-coherent devices.
  * @DEV_FLAG_OF_NODE_REUSED: Set if the device-tree node is shared with an
  *		ancestor device.
+ * @DEV_FLAG_OFFLINE_DISABLED: If set, the device is permanently online.
+ * @DEV_FLAG_OFFLINE: Set after successful invocation of bus type's .offline().
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
@@ -495,6 +497,8 @@ enum struct_device_flags {
 	DEV_FLAG_STATE_SYNCED = 5,
 	DEV_FLAG_DMA_COHERENT = 6,
 	DEV_FLAG_OF_NODE_REUSED = 7,
+	DEV_FLAG_OFFLINE_DISABLED = 8,
+	DEV_FLAG_OFFLINE = 9,
 
 	DEV_FLAG_COUNT
 };
@@ -573,9 +577,6 @@ enum struct_device_flags {
  * @removable:  Whether the device can be removed from the system. This
  *              should be set by the subsystem / bus driver that discovered
  *              the device.
- *
- * @offline_disabled: If set, the device is permanently online.
- * @offline:	Set after successful invocation of bus type's .offline().
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
@@ -680,9 +681,6 @@ struct device {
 
 	enum device_removable	removable;
 
-	bool			offline_disabled:1;
-	bool			offline:1;
-
 	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
 };
 
@@ -716,6 +714,8 @@ __create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
 __create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
 __create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
 __create_dev_flag_accessors(of_node_reused, DEV_FLAG_OF_NODE_REUSED);
+__create_dev_flag_accessors(offline_disabled, DEV_FLAG_OFFLINE_DISABLED);
+__create_dev_flag_accessors(offline, DEV_FLAG_OFFLINE);
 
 #undef __create_dev_flag_accessors
 
diff --git a/kernel/cpu.c b/kernel/cpu.c
index bc4f7a9ba64e..f975bb34915b 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2639,7 +2639,7 @@ static void cpuhp_offline_cpu_device(unsigned int cpu)
 {
 	struct device *dev = get_cpu_device(cpu);
 
-	dev->offline = true;
+	dev_set_offline(dev);
 	/* Tell user space about the state change */
 	kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
 }
@@ -2648,7 +2648,7 @@ static void cpuhp_online_cpu_device(unsigned int cpu)
 {
 	struct device *dev = get_cpu_device(cpu);
 
-	dev->offline = false;
+	dev_clear_offline(dev);
 	/* Tell user space about the state change */
 	kobject_uevent(&dev->kobj, KOBJ_ONLINE);
 }
-- 
2.53.0.1213.gd9a14994de-goog

Re: [PATCH v5 0/9] driver core: Fix some race conditions

[Marek Szyprowski]

On 07.04.2026 01:22, Douglas Anderson wrote:
> The main goal of this series is to fix the observed bug talked about
> in the first patch ("driver core: Don't let a device probe until it's
> ready"). That patch fixes a problem that has been observed in the real
> world and could land even if the rest of the patches are found
> unacceptable or need to be spun.
>
> That said, during patch review Danilo correctly pointed out that many
> of the bitfield accesses in "struct device" are unsafe. I added a
> bunch of patches in the series to address each one.
>
> Danilo said he's most worried about "can_match", so I put that one
> first. After that, I tried to transition bitfields to flags in reverse
> order to when the bitfield was added.
>
> Even if transitioning from bitfields to flags isn't truly needed for
> correctness, it seems silly (and wasteful of space in struct device)
> to have some in bitfields and some as flags. Thus I didn't spend time
> for each bitfield showing that it's truly needed for correctness.
>
> Transition was done semi manually. Presumably someone skilled at
> coccinelle could do a better job, but I just used sed in a heavy-
> handed manner and then reviewed/fixed the results, undoing anything my
> script got wrong. My terrible/ugly script was:
>
> var=can_match
> caps="${var^^}"
> for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
>   echo $f
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f"
> done
>
> From v3 to v4, I transitioned to accessor functions with another ugly
> sed script. I had git format the old patches, then transformed them
> with:
>
> for f in *.patch; do
>   echo $f
>   sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
>   sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
> done
>
> ...and then did a few manual touchups for spacing.
>
> I only marked the first patch as a "Fix" since it is the only one
> fixing observed problems. Other patches could be considered fixes too
> if folks want.
>
> I tested the first patch in the series backported to kernel 6.6 on the
> Pixel phone that was experiencing the race. I added extra printouts to
> make sure that the problem was hitting / addressed. The rest of the
> patches are tested with allmodconfig with arm32, arm64, ppc, and
> x86. I boot tested on an arm64 Chromebook running mainline.
The dma-mapping related bits are probably not race prone, but if you plan
to refactor that part I won't object.

Acked-by: Marek Szyprowski


> Changes in v5:
> - ready_to_prove => ready_to_probe typo
> - device_lock() while calling dev_set_ready_to_probe()
> - Add comment before "can_match = true" from Danilo.
> - undef __create_dev_flag_accessors
>
> Changes in v4:
> - Use accessor functions for flags
>
> Changes in v3:
> - Use a new "flags" bitfield
> - Add missing \n in probe error message
>
> Changes in v2:
> - Instead of adjusting the ordering, use "ready_to_probe" flag
>
> Douglas Anderson (9):
>   driver core: Don't let a device probe until it's ready
>   driver core: Replace dev->can_match with dev_can_match()
>   driver core: Replace dev->dma_iommu with dev_dma_iommu()
>   driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
>   driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
>   driver core: Replace dev->state_synced with dev_state_synced()
>   driver core: Replace dev->dma_coherent with dev_dma_coherent()
>   driver core: Replace dev->of_node_reused with dev_of_node_reused()
>   driver core: Replace dev->offline + ->offline_disabled with accessors
>
>  arch/arc/mm/dma.c                             |   4 +-
>  arch/arm/mach-highbank/highbank.c             |   2 +-
>  arch/arm/mach-mvebu/coherency.c               |   2 +-
>  arch/arm/mm/dma-mapping-nommu.c               |   4 +-
>  arch/arm/mm/dma-mapping.c                     |  28 ++--
>  arch/arm64/kernel/cpufeature.c                |   2 +-
>  arch/arm64/mm/dma-mapping.c                   |   2 +-
>  arch/mips/mm/dma-noncoherent.c                |   2 +-
>  arch/powerpc/kernel/dma-iommu.c               |   8 +-
>  .../platforms/pseries/hotplug-memory.c        |   4 +-
>  arch/riscv/mm/dma-noncoherent.c               |   2 +-
>  drivers/acpi/scan.c                           |   2 +-
>  drivers/base/core.c                           |  55 +++++---
>  drivers/base/cpu.c                            |   4 +-
>  drivers/base/dd.c                             |  36 ++++--
>  drivers/base/memory.c                         |   2 +-
>  drivers/base/pinctrl.c                        |   2 +-
>  drivers/base/platform.c                       |   2 +-
>  drivers/dma/ti/k3-udma-glue.c                 |   6 +-
>  drivers/dma/ti/k3-udma.c                      |   6 +-
>  drivers/iommu/dma-iommu.c                     |   9 +-
>  drivers/iommu/iommu.c                         |   5 +-
>  drivers/net/pcs/pcs-xpcs-plat.c               |   2 +-
>  drivers/of/device.c                           |   6 +-
>  drivers/pci/of.c                              |   2 +-
>  drivers/pci/pwrctrl/core.c                    |   2 +-
>  drivers/regulator/bq257xx-regulator.c         |   2 +-
>  drivers/regulator/rk808-regulator.c           |   2 +-
>  drivers/tty/serial/serial_base_bus.c          |   2 +-
>  drivers/usb/gadget/udc/aspeed-vhub/dev.c      |   2 +-
>  include/linux/device.h                        | 122 ++++++++++++------
>  include/linux/dma-map-ops.h                   |   6 +-
>  include/linux/dma-mapping.h                   |   2 +-
>  include/linux/iommu-dma.h                     |   3 +-
>  kernel/cpu.c                                  |   4 +-
>  kernel/dma/mapping.c                          |  12 +-
>  mm/hmm.c                                      |   2 +-
>  37 files changed, 218 insertions(+), 142 deletions(-)
>
Best regards

-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v5 0/9] driver core: Fix some race conditions

[Danilo Krummrich]

On Tue Apr 7, 2026 at 1:22 AM CEST, Douglas Anderson wrote:

Applied to driver-core-testing, thanks!

> Douglas Anderson (9):
>   driver core: Don't let a device probe until it's ready
>   driver core: Replace dev->can_match with dev_can_match()
>   driver core: Replace dev->dma_iommu with dev_dma_iommu()
>   driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
>   driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
>   driver core: Replace dev->state_synced with dev_state_synced()
>   driver core: Replace dev->dma_coherent with dev_dma_coherent()

    [ Since all DEV_FLAG_DMA_COHERENT accessors are exposed unconditionally,
      also drop the CONFIG guards around dev_assign_dma_coherent() in
      device_initialize() to ensure a correct default value. - Danilo ]

>   driver core: Replace dev->of_node_reused with dev_of_node_reused()
>   driver core: Replace dev->offline + ->offline_disabled with accessors