When ww_mutex_lock() returns -EDEADLK the nesting mutex-protected
section becomes a no-op. Return early and avoid the extra lock.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
---
 drivers/regulator/core.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 215b721e5cd4..921c7039baa3 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -145,18 +145,17 @@ static inline int regulator_lock_nested(struct regulator_dev *rdev,
 
 	mutex_lock(&regulator_nesting_mutex);
 
-	if (!ww_mutex_trylock(&rdev->mutex, ww_ctx)) {
-		if (rdev->mutex_owner != current) {
-			mutex_unlock(&regulator_nesting_mutex);
-			ret = ww_mutex_lock(&rdev->mutex, ww_ctx);
-			mutex_lock(&regulator_nesting_mutex);
-		}
+	if (!ww_mutex_trylock(&rdev->mutex, ww_ctx) &&
+	    rdev->mutex_owner != current) {
+		mutex_unlock(&regulator_nesting_mutex);
+		ret = ww_mutex_lock(&rdev->mutex, ww_ctx);
+		if (ret == -EDEADLK)
+			return ret;
+		mutex_lock(&regulator_nesting_mutex);
 	}
 
-	if (ret != -EDEADLK) {
-		rdev->ref_cnt++;
-		rdev->mutex_owner = current;
-	}
+	rdev->ref_cnt++;
+	rdev->mutex_owner = current;
 
 	mutex_unlock(&regulator_nesting_mutex);
 
-- 
2.39.2

Hi,

On Sat, Aug 19, 2023 at 3:46 PM Michał Mirosław <mirq-linux@rere.qmqm.pl> wrote:
>
> When ww_mutex_lock() returns -EDEADLK the nesting mutex-protected
> section becomes a no-op. Return early and avoid the extra lock.
>
> Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
> ---
>  drivers/regulator/core.c | 19 +++++++++----------
>  1 file changed, 9 insertions(+), 10 deletions(-)

Reviewed-by: Douglas Anderson <dianders@chromium.org>