[PATCH 0/9] workqueue / drivers: Add device-managed allocate workqueue

[PATCH 0/9] 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.

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 (9):
      workqueue: devres: Add device-managed allocate workqueue
      power: supply: cw2015: Free allocated workqueue
      power: supply: max77705: Free allocated workqueue and fix removal order
      power: supply: mt6370: Simplify with devm_create_singlethread_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 |  7 ++++
 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                        | 32 +++++++++++++++
 kernel/workqueue.c                               | 32 +++++++++++++++
 9 files changed, 117 insertions(+), 101 deletions(-)
---
base-commit: bc32aa8c2aea9fd3acda58dd8a5ea6c17e9dfc36
change-id: 20260220-workqueue-devm-d9591e5e70eb

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

[PATCH 2/9] 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 memory leak.

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_create_singlethread_workqueue() from earlier patches.
---
 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..1e4e3b4c7460 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_create_singlethread_workqueue(&client->dev,
+								       "rk_battery");
 	if (!cw_bat->battery_workqueue)
 		return -ENOMEM;
 

-- 
2.51.0