all first_pwq() and for_each_pwq() are converted to be protected by wq->mutex or RCU_SCHED, so freaky pwq_lock is unused.
simply remove it. Signed-off-by: Lai Jiangshan <[email protected]> --- kernel/workqueue.c | 31 +++++++++++-------------------- 1 files changed, 11 insertions(+), 20 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index a3460e7..e45f038 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -127,12 +127,9 @@ enum { * * PR: pools_mutex protected for writes. Sched-RCU protected for reads. * - * PW: pwq_lock protected. - * * Q: wq->mutex protected. * - * QR: wq->mutex and pwq_lock protected for writes. Sched-RCU - * protected for reads. + * QR: wq->mutex protected for writes. Sched-RCU protected for reads. * * MD: wq_mayday_lock protected. */ @@ -206,7 +203,7 @@ struct pool_workqueue { * Release of unbound pwq is punted to system_wq. See put_pwq() * and pwq_unbound_release_workfn() for details. pool_workqueue * itself is also sched-RCU protected so that the first pwq can be - * determined without grabbing pwq_lock. + * determined without grabbing wq->mutex. */ struct work_struct unbound_release_work; struct rcu_head rcu; @@ -260,7 +257,6 @@ static struct kmem_cache *pwq_cache; static DEFINE_MUTEX(wqs_mutex); /* protects workqueues */ static DEFINE_MUTEX(pools_mutex); /* protects pools */ -static DEFINE_SPINLOCK(pwq_lock); /* protects pool_workqueues */ static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ static LIST_HEAD(workqueues); /* QS: list of all workqueues */ @@ -301,11 +297,10 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to, lockdep_is_held(&pools_mutex), \ "sched RCU or pools_mutex should be held") -#define assert_rcu_or_pwq_lock(wq) \ +#define assert_rcu_or_wq_mutex(wq) \ rcu_lockdep_assert(rcu_read_lock_sched_held() || \ - lockdep_is_held(&wq->mutex) || \ - lockdep_is_held(&pwq_lock), \ - "sched RCU or pwq_lock should be held") + lockdep_is_held(&wq->mutex), \ + "sched RCU or wq->mutex should be held") #ifdef CONFIG_LOCKDEP #define assert_manager_or_pool_lock(pool) \ @@ -359,7 +354,7 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to, * @pwq: iteration cursor * @wq: the target workqueue * - * This must be called either with pwq_lock held or sched RCU read locked. + * This must be called either with wq->mutex held or sched RCU read locked. * If the pwq needs to be used beyond the locking in effect, the caller is * responsible for guaranteeing that the pwq stays online. * @@ -368,7 +363,7 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to, */ #define for_each_pwq(pwq, wq) \ list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node) \ - if (({ assert_rcu_or_pwq_lock(wq); false; })) { } \ + if (({ assert_rcu_or_wq_mutex(wq); false; })) { } \ else #ifdef CONFIG_DEBUG_OBJECTS_WORK @@ -507,13 +502,13 @@ static int worker_pool_assign_id(struct worker_pool *pool) * first_pwq - return the first pool_workqueue of the specified workqueue * @wq: the target workqueue * - * This must be called either with pwq_lock held or sched RCU read locked. + * This must be called either with wq->mutex held or sched RCU read locked. * If the pwq needs to be used beyond the locking in effect, the caller is * responsible for guaranteeing that the pwq stays online. */ static struct pool_workqueue *first_pwq(struct workqueue_struct *wq) { - assert_rcu_or_pwq_lock(wq); + assert_rcu_or_wq_mutex(wq); return list_first_or_null_rcu(&wq->pwqs, struct pool_workqueue, pwqs_node); } @@ -3551,9 +3546,7 @@ static void pwq_unbound_release_workfn(struct work_struct *work) * and consistent with the linking path. */ mutex_lock(&wq->mutex); - spin_lock_irq(&pwq_lock); list_del_rcu(&pwq->pwqs_node); - spin_unlock_irq(&pwq_lock); mutex_unlock(&wq->mutex); put_unbound_pool(pool); @@ -3639,9 +3632,7 @@ static void init_and_link_pwq(struct pool_workqueue *pwq, pwq_adjust_max_active(pwq); /* link in @pwq */ - spin_lock_irq(&pwq_lock); list_add_rcu(&pwq->pwqs_node, &wq->pwqs); - spin_unlock_irq(&pwq_lock); mutex_unlock(&wq->mutex); } @@ -4290,7 +4281,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu); * pool->worklist. * * CONTEXT: - * Grabs and releases wqs_mutex, pwq_lock and pool->lock's. + * Grabs and releases wqs_mutex, wq->mutex and pool->lock's. */ void freeze_workqueues_begin(void) { @@ -4377,7 +4368,7 @@ out_unlock: * frozen works are transferred to their respective pool worklists. * * CONTEXT: - * Grabs and releases wqs_mutex, pwq_lock and pool->lock's. + * Grabs and releases wqs_mutex, wq->mutex and pool->lock's. */ void thaw_workqueues(void) { -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
