[PATCH v2 00/10] workqueue / drivers: Add device-managed allocate workqueue

[PATCH v2 00/10] workqueue / drivers: Add device-managed allocate workqueue

[Krzysztof Kozlowski]

Merging / Dependency
====================
All further patches depend on the first one, thus this probably should
go via one tree, e.g. power supply.  The first patch might be needed for
other trees as well, e.g. if more drivers are discovered, so the best if
it is on dedicated branch in case it has to be shared.

Changes in v2:
==============
- See individual patches
- Link to v1: https://patch.msgid.link/20260223-workqueue-devm-v1-0-10b3a6087586@oss.qualcomm.com

Description
===========
Add a Resource-managed version of alloc_workqueue() to fix common
problem of drivers mixing devm() calls with destroy_workqueue.  Such
naive and discouraged driver approach leads to difficult to debug bugs
when the driver:

1. Allocates workqueue in standard way and destroys it in driver
remove() callback,
2. Sets work struct with devm_work_autocancel(),
3. Registers interrupt handler with devm_request_threaded_irq().

Which leads to following unbind/removal path:

1. destroy_workqueue() via driver remove(),
Any interrupt coming now would still execute the interrupt handler,
which queues work on destroyed workqueue.
2. devm_irq_release(),
3. devm_work_drop() -> cancel_work_sync() on destroyed workqueue.

devm_alloc_workqueue() has two benefits:
1. Solves above problem of mix-and-match devres and non-devres code in
driver,
2. Simplify any sane drivers which were correctly using
alloc_workqueue() + devm_add_action_or_reset().

Best regards,
Krzysztof

---
Krzysztof Kozlowski (10):
      workqueue: devres: Add device-managed allocate workqueue
      power: supply: cw2015: Free allocated workqueue
      power: supply: max77705: Drop duplicated IRQ error message
      power: supply: max77705: Free allocated workqueue and fix removal order
      power: supply: mt6370: Simplify with devm_alloc_ordered_workqueue()
      power: supply: ipaq_micro: Simplify with devm
      mfd: ezx-pcap: Drop memory allocation error message
      mfd: ezx-pcap: Return directly instead of empty gotos
      mfd: ezx-pcap: Avoid rescheduling after destroying workqueue
      platform/chrome: cros_usbpd_logger: Simplify with devm

 Documentation/driver-api/driver-model/devres.rst |  4 ++
 drivers/mfd/ezx-pcap.c                           | 27 +++++--------
 drivers/platform/chrome/cros_usbpd_logger.c      | 18 ++++-----
 drivers/power/supply/cw2015_battery.c            |  3 +-
 drivers/power/supply/ipaq_micro_battery.c        | 50 ++++++++----------------
 drivers/power/supply/max77705_charger.c          | 36 ++++++-----------
 drivers/power/supply/mt6370-charger.c            | 13 +-----
 include/linux/workqueue.h                        | 22 +++++++++++
 kernel/workqueue.c                               | 28 +++++++++++++
 9 files changed, 100 insertions(+), 101 deletions(-)
---
base-commit: 9739e59909e70058fab7a131d7bee60d447ab732
change-id: 20260220-workqueue-devm-d9591e5e70eb

Best regards,
-- 
Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

[PATCH v2 02/10] power: supply: cw2015: Free allocated workqueue

[Krzysztof Kozlowski]

Use devm interface so allocated workqueue will be freed during device
removal and error paths, thus fixing a memory leak.

Change is not equivalent in the workqueue itself: use non-legacy API
which does not set (__WQ_LEGACY | WQ_MEM_RECLAIM).  The workqueue is
used to read updated data from the battery, thus there is no point to
run it for memory reclaim.

Cc: <stable@vger.kernel.org>
Fixes: b4c7715c10c1 ("power: supply: add CellWise cw2015 fuel gauge driver")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

---

Depends on devm_xxx() from earlier patches.

Changes in v2:
1. Use devm_alloc_ordered_workqueue(), mention this in commit msg
---
 drivers/power/supply/cw2015_battery.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/cw2015_battery.c b/drivers/power/supply/cw2015_battery.c
index a05dcc4a48f2..286524d2318c 100644
--- a/drivers/power/supply/cw2015_battery.c
+++ b/drivers/power/supply/cw2015_battery.c
@@ -694,7 +694,8 @@ static int cw_bat_probe(struct i2c_client *client)
 			 "No monitored battery, some properties will be missing\n");
 	}
 
-	cw_bat->battery_workqueue = create_singlethread_workqueue("rk_battery");
+	cw_bat->battery_workqueue = devm_alloc_ordered_workqueue(&client->dev,
+								 "rk_battery", 0);
 	if (!cw_bat->battery_workqueue)
 		return -ENOMEM;
 

-- 
2.51.0

Re: [PATCH v2 00/10] workqueue / drivers: Add device-managed allocate workqueue

[Andy Shevchenko]

On Thu, Mar 05, 2026 at 10:45:39PM +0100, Krzysztof Kozlowski wrote:
> Merging / Dependency
> ====================
> All further patches depend on the first one, thus this probably should
> go via one tree, e.g. power supply.  The first patch might be needed for
> other trees as well, e.g. if more drivers are discovered, so the best if
> it is on dedicated branch in case it has to be shared.
> 
> Changes in v2:
> ==============
> - See individual patches
> - Link to v1: https://patch.msgid.link/20260223-workqueue-devm-v1-0-10b3a6087586@oss.qualcomm.com
> 
> Description
> ===========
> Add a Resource-managed version of alloc_workqueue() to fix common
> problem of drivers mixing devm() calls with destroy_workqueue.  Such
> naive and discouraged driver approach leads to difficult to debug bugs
> when the driver:
> 
> 1. Allocates workqueue in standard way and destroys it in driver
> remove() callback,
> 2. Sets work struct with devm_work_autocancel(),
> 3. Registers interrupt handler with devm_request_threaded_irq().
> 
> Which leads to following unbind/removal path:
> 
> 1. destroy_workqueue() via driver remove(),
> Any interrupt coming now would still execute the interrupt handler,
> which queues work on destroyed workqueue.
> 2. devm_irq_release(),
> 3. devm_work_drop() -> cancel_work_sync() on destroyed workqueue.
> 
> devm_alloc_workqueue() has two benefits:
> 1. Solves above problem of mix-and-match devres and non-devres code in
> driver,
> 2. Simplify any sane drivers which were correctly using
> alloc_workqueue() + devm_add_action_or_reset().

Thanks, this version LGTM, FWIW,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>


-- 
With Best Regards,
Andy Shevchenko

Re: (subset) [PATCH v2 00/10] workqueue / drivers: Add device-managed allocate workqueue

[Sebastian Reichel]

On Thu, 05 Mar 2026 22:45:39 +0100, Krzysztof Kozlowski wrote:
> Merging / Dependency
> ====================
> All further patches depend on the first one, thus this probably should
> go via one tree, e.g. power supply.  The first patch might be needed for
> other trees as well, e.g. if more drivers are discovered, so the best if
> it is on dedicated branch in case it has to be shared.
> 
> [...]

Applied, thanks!

[02/10] power: supply: cw2015: Free allocated workqueue
        commit: db254b0b232358ab1aeadebe8d147c99a3569559
[03/10] power: supply: max77705: Drop duplicated IRQ error message
        commit: 2064c64ceb1996ee02a6bbb1de05fd6e8028e3e4
[04/10] power: supply: max77705: Free allocated workqueue and fix removal order
        commit: 1e668baadefb16e81269dbfebf3ffc2672e3a3bb
[05/10] power: supply: mt6370: Simplify with devm_alloc_ordered_workqueue()
        commit: f23afa01040a41882a048e4957a7acac1426da6f
[06/10] power: supply: ipaq_micro: Simplify with devm
        commit: 2cfc7cac68e19c4acb236b8db6065bbaff5deee8

Best regards,
-- 
Sebastian Reichel <sebastian.reichel@collabora.com>

Re: (subset) [PATCH v2 00/10] workqueue / drivers: Add device-managed allocate workqueue

[Lee Jones]

On Thu, 05 Mar 2026 22:45:39 +0100, Krzysztof Kozlowski wrote:
> Merging / Dependency
> ====================
> All further patches depend on the first one, thus this probably should
> go via one tree, e.g. power supply.  The first patch might be needed for
> other trees as well, e.g. if more drivers are discovered, so the best if
> it is on dedicated branch in case it has to be shared.
> 
> [...]

Applied, thanks!

[07/10] mfd: ezx-pcap: Drop memory allocation error message
        commit: 33e0316783a205625b7c55a78041ddc0d5dce7c7
[08/10] mfd: ezx-pcap: Return directly instead of empty gotos
        commit: 444e11d9d9e56c994da8a253cdf7f33ac2eeb15b
[09/10] mfd: ezx-pcap: Avoid rescheduling after destroying workqueue
        commit: 356ee03f6ae7d04f90d8e2104660193c4f3a071c

--
Lee Jones [李琼斯]

Re: (subset) [PATCH v2 00/10] workqueue / drivers: Add device-managed allocate workqueue

[Tzung-Bi Shih]

On Thu, Mar 05, 2026 at 10:45:39PM +0100, Krzysztof Kozlowski wrote:
> Merging / Dependency
> ====================
> All further patches depend on the first one, thus this probably should
> go via one tree, e.g. power supply.  The first patch might be needed for
> other trees as well, e.g. if more drivers are discovered, so the best if
> it is on dedicated branch in case it has to be shared.
> 
> [...]

Applied to

    https://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux.git for-next

[10/10] platform/chrome: cros_usbpd_logger: Simplify with devm
        commit: 168e4b208ca8c2e04de20cc6cb7e2fb035dc1ec8

Thanks!