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workqueue: rename wq_mutex to wq_pool_mutex

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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 <tj@kernel.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
This commit is contained in:
Lai Jiangshan 2013-03-25 16:57:17 -07:00 committed by Tejun Heo
parent 519e3c1163
commit 68e13a67dd
1 changed files with 55 additions and 54 deletions
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109
kernel/workqueue.c
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@ -123,9 +123,9 @@ enum {
* MG: pool->manager_mutex and pool->lock protected. Writes require both * MG: pool->manager_mutex and pool->lock protected. Writes require both
* locks. Reads can happen under either lock. * 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. * PW: pwq_lock protected.
* *
@ -163,8 +163,8 @@ struct worker_pool {
struct idr worker_idr; /* MG: worker IDs and iteration */ struct idr worker_idr; /* MG: worker IDs and iteration */
struct workqueue_attrs *attrs; /* I: worker attributes */ struct workqueue_attrs *attrs; /* I: worker attributes */
struct hlist_node hash_node; /* WQ: unbound_pool_hash node */ struct hlist_node hash_node; /* PL: unbound_pool_hash node */
int refcnt; /* WQ: refcnt for unbound pools */ int refcnt; /* PL: refcnt for unbound pools */
/* /*
* The current concurrency level. As it's likely to be accessed * 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. * the appropriate worker_pool through its pool_workqueues.
*/ */
struct workqueue_struct { 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 pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwq's */
struct list_head pwqs; /* FR: all pwqs of this wq */ 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 */ struct mutex flush_mutex; /* protects wq flushing */
int work_color; /* F: current work color */ int work_color; /* F: current work color */
@ -242,7 +242,7 @@ struct workqueue_struct {
struct list_head maydays; /* MD: pwqs requesting rescue */ struct list_head maydays; /* MD: pwqs requesting rescue */
struct worker *rescuer; /* I: rescue worker */ 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 */ int saved_max_active; /* PW: saved pwq max_active */
#ifdef CONFIG_SYSFS #ifdef CONFIG_SYSFS
@ -256,20 +256,20 @@ struct workqueue_struct {
static struct kmem_cache *pwq_cache; 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(pwq_lock); /* protects pool_workqueues */
static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */
static LIST_HEAD(workqueues); /* WQ: list of all workqueues */ static LIST_HEAD(workqueues); /* PL: list of all workqueues */
static bool workqueue_freezing; /* WQ: have wqs started freezing? */ static bool workqueue_freezing; /* PL: have wqs started freezing? */
/* the per-cpu worker pools */ /* the per-cpu worker pools */
static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS],
cpu_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); static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER);
/* I: attributes used when instantiating standard unbound pools on demand */ /* 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 #define CREATE_TRACE_POINTS
#include <trace/events/workqueue.h> #include <trace/events/workqueue.h>
#define assert_rcu_or_wq_mutex() \ #define assert_rcu_or_pool_mutex() \
rcu_lockdep_assert(rcu_read_lock_sched_held() || \ rcu_lockdep_assert(rcu_read_lock_sched_held() || \
lockdep_is_held(&wq_mutex), \ lockdep_is_held(&wq_pool_mutex), \
"sched RCU or wq_mutex should be held") "sched RCU or wq_pool_mutex should be held")
#define assert_rcu_or_pwq_lock() \ #define assert_rcu_or_pwq_lock() \
rcu_lockdep_assert(rcu_read_lock_sched_held() || \ rcu_lockdep_assert(rcu_read_lock_sched_held() || \
@ -323,16 +323,16 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to,
* @pool: iteration cursor * @pool: iteration cursor
* @pi: integer used for iteration * @pi: integer used for iteration
* *
* This must be called either with wq_mutex held or sched RCU read locked. * This must be called either with wq_pool_mutex held or sched RCU read
* If the pool needs to be used beyond the locking in effect, the caller is * locked. If the pool needs to be used beyond the locking in effect, the
* responsible for guaranteeing that the pool stays online. * caller is responsible for guaranteeing that the pool stays online.
* *
* The if/else clause exists only for the lockdep assertion and can be * The if/else clause exists only for the lockdep assertion and can be
* ignored. * ignored.
*/ */
#define for_each_pool(pool, pi) \ #define for_each_pool(pool, pi) \
idr_for_each_entry(&worker_pool_idr, 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 else
/** /**
@ -489,7 +489,7 @@ static int worker_pool_assign_id(struct worker_pool *pool)
{ {
int ret; int ret;
lockdep_assert_held(&wq_mutex); lockdep_assert_held(&wq_pool_mutex);
do { do {
if (!idr_pre_get(&worker_pool_idr, GFP_KERNEL)) 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. * Return the worker_pool @work was last associated with. %NULL if none.
* *
* Pools are created and destroyed under wq_mutex, and allows read access * Pools are created and destroyed under wq_pool_mutex, and allows read
* under sched-RCU read lock. As such, this function should be called * access under sched-RCU read lock. As such, this function should be
* under wq_mutex or with preemption disabled. * called under wq_pool_mutex or with preemption disabled.
* *
* All fields of the returned pool are accessible as long as the above * 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 * 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); unsigned long data = atomic_long_read(&work->data);
int pool_id; int pool_id;
assert_rcu_or_wq_mutex(); assert_rcu_or_pool_mutex();
if (data & WORK_STRUCT_PWQ) if (data & WORK_STRUCT_PWQ)
return ((struct pool_workqueue *) 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. * hotter than drain_workqueue() and already looks at @wq->flags.
* Use __WQ_DRAINING so that queue doesn't have to check nr_drainers. * 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++) if (!wq->nr_drainers++)
wq->flags |= __WQ_DRAINING; wq->flags |= __WQ_DRAINING;
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
reflush: reflush:
flush_workqueue(wq); flush_workqueue(wq);
@ -2714,10 +2714,10 @@ void drain_workqueue(struct workqueue_struct *wq)
local_irq_enable(); local_irq_enable();
mutex_lock(&wq_mutex); mutex_lock(&wq_pool_mutex);
if (!--wq->nr_drainers) if (!--wq->nr_drainers)
wq->flags &= ~__WQ_DRAINING; wq->flags &= ~__WQ_DRAINING;
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
} }
EXPORT_SYMBOL_GPL(drain_workqueue); EXPORT_SYMBOL_GPL(drain_workqueue);
@ -3430,16 +3430,16 @@ static void put_unbound_pool(struct worker_pool *pool)
{ {
struct worker *worker; struct worker *worker;
mutex_lock(&wq_mutex); mutex_lock(&wq_pool_mutex);
if (--pool->refcnt) { if (--pool->refcnt) {
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
return; return;
} }
/* sanity checks */ /* sanity checks */
if (WARN_ON(!(pool->flags & POOL_DISASSOCIATED)) || if (WARN_ON(!(pool->flags & POOL_DISASSOCIATED)) ||
WARN_ON(!list_empty(&pool->worklist))) { WARN_ON(!list_empty(&pool->worklist))) {
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
return; return;
} }
@ -3448,7 +3448,7 @@ static void put_unbound_pool(struct worker_pool *pool)
idr_remove(&worker_pool_idr, pool->id); idr_remove(&worker_pool_idr, pool->id);
hash_del(&pool->hash_node); hash_del(&pool->hash_node);
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
/* /*
* Become the manager and destroy all workers. Grabbing * 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); u32 hash = wqattrs_hash(attrs);
struct worker_pool *pool; struct worker_pool *pool;
mutex_lock(&wq_mutex); mutex_lock(&wq_pool_mutex);
/* do we already have a matching pool? */ /* do we already have a matching pool? */
hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) { 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 */ /* install */
hash_add(unbound_pool_hash, &pool->hash_node, hash); hash_add(unbound_pool_hash, &pool->hash_node, hash);
out_unlock: out_unlock:
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
return pool; return pool;
fail: fail:
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
if (pool) if (pool)
put_unbound_pool(pool); put_unbound_pool(pool);
return NULL; return NULL;
@ -3803,10 +3803,11 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
goto err_destroy; goto err_destroy;
/* /*
* wq_mutex protects global freeze state and workqueues list. Grab * wq_pool_mutex protects global freeze state and workqueues list.
* it, adjust max_active and add the new @wq to 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); spin_lock_irq(&pwq_lock);
for_each_pwq(pwq, wq) for_each_pwq(pwq, wq)
@ -3815,7 +3816,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
list_add(&wq->list, &workqueues); list_add(&wq->list, &workqueues);
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
return wq; return wq;
@ -3866,9 +3867,9 @@ void destroy_workqueue(struct workqueue_struct *wq)
* wq list is used to freeze wq, remove from list after * wq list is used to freeze wq, remove from list after
* flushing is complete in case freeze races us. * flushing is complete in case freeze races us.
*/ */
mutex_lock(&wq_mutex); mutex_lock(&wq_pool_mutex);
list_del_init(&wq->list); list_del_init(&wq->list);
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
workqueue_sysfs_unregister(wq); 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_DOWN_FAILED:
case CPU_ONLINE: case CPU_ONLINE:
mutex_lock(&wq_mutex); mutex_lock(&wq_pool_mutex);
for_each_pool(pool, pi) { for_each_pool(pool, pi) {
mutex_lock(&pool->manager_mutex); 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(&pool->manager_mutex);
} }
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
break; break;
} }
return NOTIFY_OK; return NOTIFY_OK;
@ -4292,7 +4293,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu);
* pool->worklist. * pool->worklist.
* *
* CONTEXT: * 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) void freeze_workqueues_begin(void)
{ {
@ -4301,7 +4302,7 @@ void freeze_workqueues_begin(void)
struct pool_workqueue *pwq; struct pool_workqueue *pwq;
int pi; int pi;
mutex_lock(&wq_mutex); mutex_lock(&wq_pool_mutex);
WARN_ON_ONCE(workqueue_freezing); WARN_ON_ONCE(workqueue_freezing);
workqueue_freezing = true; workqueue_freezing = true;
@ -4322,7 +4323,7 @@ void freeze_workqueues_begin(void)
} }
spin_unlock_irq(&pwq_lock); 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(). * between freeze_workqueues_begin() and thaw_workqueues().
* *
* CONTEXT: * CONTEXT:
* Grabs and releases wq_mutex. * Grabs and releases wq_pool_mutex.
* *
* RETURNS: * RETURNS:
* %true if some freezable workqueues are still busy. %false if freezing * %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 workqueue_struct *wq;
struct pool_workqueue *pwq; struct pool_workqueue *pwq;
mutex_lock(&wq_mutex); mutex_lock(&wq_pool_mutex);
WARN_ON_ONCE(!workqueue_freezing); WARN_ON_ONCE(!workqueue_freezing);
@ -4367,7 +4368,7 @@ bool freeze_workqueues_busy(void)
rcu_read_unlock_sched(); rcu_read_unlock_sched();
} }
out_unlock: out_unlock:
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
return busy; return busy;
} }
@ -4378,7 +4379,7 @@ bool freeze_workqueues_busy(void)
* frozen works are transferred to their respective pool worklists. * frozen works are transferred to their respective pool worklists.
* *
* CONTEXT: * 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) void thaw_workqueues(void)
{ {
@ -4387,7 +4388,7 @@ void thaw_workqueues(void)
struct worker_pool *pool; struct worker_pool *pool;
int pi; int pi;
mutex_lock(&wq_mutex); mutex_lock(&wq_pool_mutex);
if (!workqueue_freezing) if (!workqueue_freezing)
goto out_unlock; goto out_unlock;
@ -4410,7 +4411,7 @@ void thaw_workqueues(void)
workqueue_freezing = false; workqueue_freezing = false;
out_unlock: out_unlock:
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
} }
#endif /* CONFIG_FREEZER */ #endif /* CONFIG_FREEZER */
@ -4442,9 +4443,9 @@ static int __init init_workqueues(void)
pool->attrs->nice = std_nice[i++]; pool->attrs->nice = std_nice[i++];
/* alloc pool ID */ /* alloc pool ID */
mutex_lock(&wq_mutex); mutex_lock(&wq_pool_mutex);
BUG_ON(worker_pool_assign_id(pool)); BUG_ON(worker_pool_assign_id(pool));
mutex_unlock(&wq_mutex); mutex_unlock(&wq_pool_mutex);
} }
} }