From 68e13a67ddfb55af386b903ab9ca56358930f79c Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Mon, 25 Mar 2013 16:57:17 -0700 Subject: [PATCH] workqueue: rename wq_mutex to wq_pool_mutex wq->flush_mutex will be renamed to wq->mutex and cover all fields specific to each workqueue and eventually replace pwq_lock, which will make locking simpler and easier to understand. Rename wq_mutex to wq_pool_mutex to avoid confusion with wq->mutex. After the scheduled changes, wq_pool_mutex won't be protecting anything specific to each workqueue instance anyway. This patch is pure rename. tj: s/wqs_mutex/wq_pool_mutex/. Rewrote description. Signed-off-by: Tejun Heo Cc: Lai Jiangshan --- kernel/workqueue.c | 109 +++++++++++++++++++++++---------------------- 1 file changed, 55 insertions(+), 54 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 47f258799bf2..064157eac4c8 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -123,9 +123,9 @@ enum { * MG: pool->manager_mutex and pool->lock protected. Writes require both * locks. Reads can happen under either lock. * - * WQ: wq_mutex protected. + * PL: wq_pool_mutex protected. * - * WR: wq_mutex protected for writes. Sched-RCU protected for reads. + * PR: wq_pool_mutex protected for writes. Sched-RCU protected for reads. * * PW: pwq_lock protected. * @@ -163,8 +163,8 @@ struct worker_pool { struct idr worker_idr; /* MG: worker IDs and iteration */ struct workqueue_attrs *attrs; /* I: worker attributes */ - struct hlist_node hash_node; /* WQ: unbound_pool_hash node */ - int refcnt; /* WQ: refcnt for unbound pools */ + struct hlist_node hash_node; /* PL: unbound_pool_hash node */ + int refcnt; /* PL: refcnt for unbound pools */ /* * The current concurrency level. As it's likely to be accessed @@ -226,10 +226,10 @@ struct wq_device; * the appropriate worker_pool through its pool_workqueues. */ struct workqueue_struct { - unsigned int flags; /* WQ: WQ_* flags */ + unsigned int flags; /* PL: WQ_* flags */ struct pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwq's */ struct list_head pwqs; /* FR: all pwqs of this wq */ - struct list_head list; /* WQ: list of all workqueues */ + struct list_head list; /* PL: list of all workqueues */ struct mutex flush_mutex; /* protects wq flushing */ int work_color; /* F: current work color */ @@ -242,7 +242,7 @@ struct workqueue_struct { struct list_head maydays; /* MD: pwqs requesting rescue */ struct worker *rescuer; /* I: rescue worker */ - int nr_drainers; /* WQ: drain in progress */ + int nr_drainers; /* PL: drain in progress */ int saved_max_active; /* PW: saved pwq max_active */ #ifdef CONFIG_SYSFS @@ -256,20 +256,20 @@ struct workqueue_struct { static struct kmem_cache *pwq_cache; -static DEFINE_MUTEX(wq_mutex); /* protects workqueues and pools */ +static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */ static DEFINE_SPINLOCK(pwq_lock); /* protects pool_workqueues */ static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ -static LIST_HEAD(workqueues); /* WQ: list of all workqueues */ -static bool workqueue_freezing; /* WQ: have wqs started freezing? */ +static LIST_HEAD(workqueues); /* PL: list of all workqueues */ +static bool workqueue_freezing; /* PL: have wqs started freezing? */ /* the per-cpu worker pools */ static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], cpu_worker_pools); -static DEFINE_IDR(worker_pool_idr); /* WR: idr of all pools */ +static DEFINE_IDR(worker_pool_idr); /* PR: idr of all pools */ -/* WQ: hash of all unbound pools keyed by pool->attrs */ +/* PL: hash of all unbound pools keyed by pool->attrs */ static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER); /* I: attributes used when instantiating standard unbound pools on demand */ @@ -293,10 +293,10 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to, #define CREATE_TRACE_POINTS #include -#define assert_rcu_or_wq_mutex() \ +#define assert_rcu_or_pool_mutex() \ rcu_lockdep_assert(rcu_read_lock_sched_held() || \ - lockdep_is_held(&wq_mutex), \ - "sched RCU or wq_mutex should be held") + lockdep_is_held(&wq_pool_mutex), \ + "sched RCU or wq_pool_mutex should be held") #define assert_rcu_or_pwq_lock() \ rcu_lockdep_assert(rcu_read_lock_sched_held() || \ @@ -323,16 +323,16 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to, * @pool: iteration cursor * @pi: integer used for iteration * - * This must be called either with wq_mutex held or sched RCU read locked. - * If the pool needs to be used beyond the locking in effect, the caller is - * responsible for guaranteeing that the pool stays online. + * This must be called either with wq_pool_mutex held or sched RCU read + * locked. If the pool needs to be used beyond the locking in effect, the + * caller is responsible for guaranteeing that the pool stays online. * * The if/else clause exists only for the lockdep assertion and can be * ignored. */ #define for_each_pool(pool, pi) \ idr_for_each_entry(&worker_pool_idr, pool, pi) \ - if (({ assert_rcu_or_wq_mutex(); false; })) { } \ + if (({ assert_rcu_or_pool_mutex(); false; })) { } \ else /** @@ -489,7 +489,7 @@ static int worker_pool_assign_id(struct worker_pool *pool) { int ret; - lockdep_assert_held(&wq_mutex); + lockdep_assert_held(&wq_pool_mutex); do { if (!idr_pre_get(&worker_pool_idr, GFP_KERNEL)) @@ -607,9 +607,9 @@ static struct pool_workqueue *get_work_pwq(struct work_struct *work) * * Return the worker_pool @work was last associated with. %NULL if none. * - * Pools are created and destroyed under wq_mutex, and allows read access - * under sched-RCU read lock. As such, this function should be called - * under wq_mutex or with preemption disabled. + * Pools are created and destroyed under wq_pool_mutex, and allows read + * access under sched-RCU read lock. As such, this function should be + * called under wq_pool_mutex or with preemption disabled. * * All fields of the returned pool are accessible as long as the above * mentioned locking is in effect. If the returned pool needs to be used @@ -621,7 +621,7 @@ static struct worker_pool *get_work_pool(struct work_struct *work) unsigned long data = atomic_long_read(&work->data); int pool_id; - assert_rcu_or_wq_mutex(); + assert_rcu_or_pool_mutex(); if (data & WORK_STRUCT_PWQ) return ((struct pool_workqueue *) @@ -2684,10 +2684,10 @@ void drain_workqueue(struct workqueue_struct *wq) * hotter than drain_workqueue() and already looks at @wq->flags. * Use __WQ_DRAINING so that queue doesn't have to check nr_drainers. */ - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); if (!wq->nr_drainers++) wq->flags |= __WQ_DRAINING; - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); reflush: flush_workqueue(wq); @@ -2714,10 +2714,10 @@ reflush: local_irq_enable(); - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); if (!--wq->nr_drainers) wq->flags &= ~__WQ_DRAINING; - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); } EXPORT_SYMBOL_GPL(drain_workqueue); @@ -3430,16 +3430,16 @@ static void put_unbound_pool(struct worker_pool *pool) { struct worker *worker; - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); if (--pool->refcnt) { - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); return; } /* sanity checks */ if (WARN_ON(!(pool->flags & POOL_DISASSOCIATED)) || WARN_ON(!list_empty(&pool->worklist))) { - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); return; } @@ -3448,7 +3448,7 @@ static void put_unbound_pool(struct worker_pool *pool) idr_remove(&worker_pool_idr, pool->id); hash_del(&pool->hash_node); - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); /* * Become the manager and destroy all workers. Grabbing @@ -3489,7 +3489,7 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) u32 hash = wqattrs_hash(attrs); struct worker_pool *pool; - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); /* do we already have a matching pool? */ hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) { @@ -3520,10 +3520,10 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) /* install */ hash_add(unbound_pool_hash, &pool->hash_node, hash); out_unlock: - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); return pool; fail: - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); if (pool) put_unbound_pool(pool); return NULL; @@ -3803,10 +3803,11 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, goto err_destroy; /* - * wq_mutex protects global freeze state and workqueues list. Grab - * it, adjust max_active and add the new @wq to workqueues list. + * wq_pool_mutex protects global freeze state and workqueues list. + * Grab it, adjust max_active and add the new @wq to workqueues + * list. */ - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); spin_lock_irq(&pwq_lock); for_each_pwq(pwq, wq) @@ -3815,7 +3816,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, list_add(&wq->list, &workqueues); - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); return wq; @@ -3866,9 +3867,9 @@ void destroy_workqueue(struct workqueue_struct *wq) * wq list is used to freeze wq, remove from list after * flushing is complete in case freeze races us. */ - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); list_del_init(&wq->list); - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); workqueue_sysfs_unregister(wq); @@ -4198,7 +4199,7 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, case CPU_DOWN_FAILED: case CPU_ONLINE: - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); for_each_pool(pool, pi) { mutex_lock(&pool->manager_mutex); @@ -4216,7 +4217,7 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, mutex_unlock(&pool->manager_mutex); } - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); break; } return NOTIFY_OK; @@ -4292,7 +4293,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu); * pool->worklist. * * CONTEXT: - * Grabs and releases wq_mutex, pwq_lock and pool->lock's. + * Grabs and releases wq_pool_mutex, pwq_lock and pool->lock's. */ void freeze_workqueues_begin(void) { @@ -4301,7 +4302,7 @@ void freeze_workqueues_begin(void) struct pool_workqueue *pwq; int pi; - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); WARN_ON_ONCE(workqueue_freezing); workqueue_freezing = true; @@ -4322,7 +4323,7 @@ void freeze_workqueues_begin(void) } spin_unlock_irq(&pwq_lock); - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); } /** @@ -4332,7 +4333,7 @@ void freeze_workqueues_begin(void) * between freeze_workqueues_begin() and thaw_workqueues(). * * CONTEXT: - * Grabs and releases wq_mutex. + * Grabs and releases wq_pool_mutex. * * RETURNS: * %true if some freezable workqueues are still busy. %false if freezing @@ -4344,7 +4345,7 @@ bool freeze_workqueues_busy(void) struct workqueue_struct *wq; struct pool_workqueue *pwq; - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); WARN_ON_ONCE(!workqueue_freezing); @@ -4367,7 +4368,7 @@ bool freeze_workqueues_busy(void) rcu_read_unlock_sched(); } out_unlock: - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); return busy; } @@ -4378,7 +4379,7 @@ out_unlock: * frozen works are transferred to their respective pool worklists. * * CONTEXT: - * Grabs and releases wq_mutex, pwq_lock and pool->lock's. + * Grabs and releases wq_pool_mutex, pwq_lock and pool->lock's. */ void thaw_workqueues(void) { @@ -4387,7 +4388,7 @@ void thaw_workqueues(void) struct worker_pool *pool; int pi; - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); if (!workqueue_freezing) goto out_unlock; @@ -4410,7 +4411,7 @@ void thaw_workqueues(void) workqueue_freezing = false; out_unlock: - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); } #endif /* CONFIG_FREEZER */ @@ -4442,9 +4443,9 @@ static int __init init_workqueues(void) pool->attrs->nice = std_nice[i++]; /* alloc pool ID */ - mutex_lock(&wq_mutex); + mutex_lock(&wq_pool_mutex); BUG_ON(worker_pool_assign_id(pool)); - mutex_unlock(&wq_mutex); + mutex_unlock(&wq_pool_mutex); } } -- 2.30.2