Messages in this thread Patch in this message | | | Date | Wed, 30 Aug 2023 19:35:31 +0200 | Subject | [PATCH v2 3/7] regulator/core: regulator_lock_nested: simplify nested locking | From | Michał Mirosław <> |
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Simplify regulator locking by removing locking around locking. rdev->ref check when unlocking is moved inside the critical section.
This patch depends on commit 12235da8c80a ("kernel/locking: Add context to ww_mutex_trylock()").
Note: return -EALREADY is removed as no caller depends on it and in that case the lock count is incremented anyway.
Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> --- drivers/regulator/core.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 921c7039baa3..f18e7cb88a0d 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -34,7 +34,6 @@ #include "internal.h" static DEFINE_WW_CLASS(regulator_ww_class); -static DEFINE_MUTEX(regulator_nesting_mutex); static DEFINE_MUTEX(regulator_list_mutex); static LIST_HEAD(regulator_map_list); static LIST_HEAD(regulator_ena_gpio_list); @@ -141,25 +140,18 @@ static bool regulator_ops_is_valid(struct regulator_dev *rdev, int ops) static inline int regulator_lock_nested(struct regulator_dev *rdev, struct ww_acquire_ctx *ww_ctx) { - int ret = 0; - - mutex_lock(®ulator_nesting_mutex); - if (!ww_mutex_trylock(&rdev->mutex, ww_ctx) && - rdev->mutex_owner != current) { - mutex_unlock(®ulator_nesting_mutex); - ret = ww_mutex_lock(&rdev->mutex, ww_ctx); + READ_ONCE(rdev->mutex_owner) != current) { + int ret = ww_mutex_lock(&rdev->mutex, ww_ctx); + if (ret == -EDEADLK) return ret; - mutex_lock(®ulator_nesting_mutex); } rdev->ref_cnt++; rdev->mutex_owner = current; - mutex_unlock(®ulator_nesting_mutex); - - return ret; + return 0; } /** @@ -186,16 +178,13 @@ static void regulator_lock(struct regulator_dev *rdev) */ static void regulator_unlock(struct regulator_dev *rdev) { - mutex_lock(®ulator_nesting_mutex); + if (WARN_ON_ONCE(rdev->ref_cnt <= 0)) + return; if (--rdev->ref_cnt == 0) { rdev->mutex_owner = NULL; ww_mutex_unlock(&rdev->mutex); } - - WARN_ON_ONCE(rdev->ref_cnt < 0); - - mutex_unlock(®ulator_nesting_mutex); } /** -- 2.39.2
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