Messages in this thread Patch in this message | | | Date | Thu, 17 Aug 2023 20:52:05 +0200 | Subject | [PATCH] regulator: simplify nested locking | From | Michał Mirosław <> |
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Simplify regulator locking by removing locking around locking. rdev->ref is now accessed only when the lock is taken.
This patch depends on 12235da8c80a ("kernel/locking: Add context to ww_mutex_trylock()").
Fixes: f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking") Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> --- drivers/regulator/core.c | 40 +++++--------------------------- include/linux/regulator/driver.h | 1 - 2 files changed, 6 insertions(+), 35 deletions(-)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index d8e1caaf207e..0e3fba9eb5d4 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); @@ -141,32 +140,13 @@ 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) { - bool lock = false; int ret = 0; - mutex_lock(®ulator_nesting_mutex); + if (!ww_mutex_trylock(&rdev->mutex, ww_ctx)) + ret = ww_mutex_lock(&rdev->mutex, ww_ctx); - if (!ww_mutex_trylock(&rdev->mutex, ww_ctx)) { - if (rdev->mutex_owner == current) - rdev->ref_cnt++; - else - lock = true; - - if (lock) { - mutex_unlock(®ulator_nesting_mutex); - ret = ww_mutex_lock(&rdev->mutex, ww_ctx); - mutex_lock(®ulator_nesting_mutex); - } - } else { - lock = true; - } - - if (lock && ret != -EDEADLK) { + if (ret != -EDEADLK) rdev->ref_cnt++; - rdev->mutex_owner = current; - } - - mutex_unlock(®ulator_nesting_mutex); return ret; } @@ -195,16 +175,11 @@ 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; + if (--rdev->ref_cnt == 0) ww_mutex_unlock(&rdev->mutex); - } - - WARN_ON_ONCE(rdev->ref_cnt < 0); - - mutex_unlock(®ulator_nesting_mutex); } /** @@ -240,7 +215,6 @@ static void regulator_lock_two(struct regulator_dev *rdev1, ww_mutex_lock_slow(&contended->mutex, ww_ctx); contended->ref_cnt++; - contended->mutex_owner = current; swap(held, contended); ret = regulator_lock_nested(contended, ww_ctx); @@ -399,7 +373,6 @@ static void regulator_lock_dependent(struct regulator_dev *rdev, ww_mutex_lock_slow(&new_contended_rdev->mutex, ww_ctx); old_contended_rdev = new_contended_rdev; old_contended_rdev->ref_cnt++; - old_contended_rdev->mutex_owner = current; } err = regulator_lock_recursive(rdev, @@ -6113,7 +6086,6 @@ static void regulator_summary_lock(struct ww_acquire_ctx *ww_ctx) ww_mutex_lock_slow(&new_contended_rdev->mutex, ww_ctx); old_contended_rdev = new_contended_rdev; old_contended_rdev->ref_cnt++; - old_contended_rdev->mutex_owner = current; } err = regulator_summary_lock_all(ww_ctx, diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h index c6ef7d68eb9a..3ed9fa385593 100644 --- a/include/linux/regulator/driver.h +++ b/include/linux/regulator/driver.h @@ -625,7 +625,6 @@ struct regulator_dev { struct blocking_notifier_head notifier; struct ww_mutex mutex; /* consumer lock */ - struct task_struct *mutex_owner; int ref_cnt; struct module *owner; struct device dev; -- 2.39.2
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