[PATCH V3 08/10] workqueue: rename manager_mutex to attach_mutex

Lai Jiangshan
2014-05-20T09:43:43Z

manager_mutex is only used to protect the attaching for the pool
and the pool->workers list. It protects the pool->workers and operations
based on this list, such as:
cpu-binding for the workers in the pool->workers
the operations to set/clear WORKER_UNBOUND

So we can simply rename manager_mutex to attach_mutex without any
functionality changed.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
kernel/workqueue.c | 44 +++++++++++++++++++++---------------------
kernel/workqueue_internal.h | 4 +-
2 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4ae6a3c..728b515 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -65,7 +65,7 @@ enum {
* be executing on any CPU. The pool behaves as an unbound one.
*
* Note that DISASSOCIATED should be flipped only while holding
- * manager_mutex to avoid changing binding state while
+ * attach_mutex to avoid changing binding state while
* create_worker() is in progress.
*/
POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */
@@ -122,7 +122,7 @@ enum {
* cpu or grabbing pool->lock is enough for read access. If
* POOL_DISASSOCIATED is set, it's identical to L.
*
- * M: pool->manager_mutex protected.
+ * A: pool->attach_mutex protected.
*
* PL: wq_pool_mutex protected.
*
@@ -160,8 +160,8 @@ struct worker_pool {

/* see manage_workers() for details on the two manager mutexes */
struct mutex manager_arb; /* manager arbitration */
- struct mutex manager_mutex; /* manager exclusion */
- struct list_head workers; /* M: attached workers */
+ struct mutex attach_mutex; /* attach/detach exclusion */
+ struct list_head workers; /* A: attached workers */
struct completion *detach_completion; /* all workers detached */

struct ida worker_ida; /* worker IDs for task name */
@@ -367,14 +367,14 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to,
* @worker: iteration cursor
* @pool: worker_pool to iterate workers of
*
- * This must be called with @pool->manager_mutex.
+ * This must be called with @pool->attach_mutex.
*
* The if/else clause exists only for the lockdep assertion and can be
* ignored.
*/
#define for_each_pool_worker(worker, pool) \
list_for_each_entry((worker), &(pool)->workers, node) \
- if (({ lockdep_assert_held(&pool->manager_mutex); false; })) { } \
+ if (({ lockdep_assert_held(&pool->attach_mutex); false; })) { } \
else

/**
@@ -1696,11 +1696,11 @@ static void worker_detach_from_pool(struct worker *worker,
{
struct completion *detach_completion = NULL;

- mutex_lock(&pool->manager_mutex);
+ mutex_lock(&pool->attach_mutex);
list_del(&worker->node);
if (list_empty(&pool->workers))
detach_completion = pool->detach_completion;
- mutex_unlock(&pool->manager_mutex);
+ mutex_unlock(&pool->attach_mutex);

if (detach_completion)
complete(detach_completion);
@@ -1753,7 +1753,7 @@ static struct worker *create_worker(struct worker_pool *pool)
/* prevent userland from meddling with cpumask of workqueue workers */
worker->task->flags |= PF_NO_SETAFFINITY;

- mutex_lock(&pool->manager_mutex);
+ mutex_lock(&pool->attach_mutex);

/*
* set_cpus_allowed_ptr() will fail if the cpumask doesn't have any
@@ -1762,7 +1762,7 @@ static struct worker *create_worker(struct worker_pool *pool)
set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);

/*
- * The pool->manager_mutex ensures %POOL_DISASSOCIATED
+ * The pool->attach_mutex ensures %POOL_DISASSOCIATED
* remains stable across this function. See the comments above the
* flag definition for details.
*/
@@ -1772,7 +1772,7 @@ static struct worker *create_worker(struct worker_pool *pool)
/* successful, attach the worker to the pool */
list_add_tail(&worker->node, &pool->workers);

- mutex_unlock(&pool->manager_mutex);
+ mutex_unlock(&pool->attach_mutex);

return worker;

@@ -3456,7 +3456,7 @@ static int init_worker_pool(struct worker_pool *pool)
(unsigned long)pool);

mutex_init(&pool->manager_arb);
- mutex_init(&pool->manager_mutex);
+ mutex_init(&pool->attach_mutex);
INIT_LIST_HEAD(&pool->workers);

ida_init(&pool->worker_ida);
@@ -3513,7 +3513,7 @@ static void put_unbound_pool(struct worker_pool *pool)
/*
* Become the manager and destroy all workers. Grabbing
* manager_arb prevents @pool's workers from blocking on
- * manager_mutex.
+ * attach_mutex.
*/
mutex_lock(&pool->manager_arb);

@@ -3523,10 +3523,10 @@ static void put_unbound_pool(struct worker_pool *pool)
WARN_ON(pool->nr_workers || pool->nr_idle);
spin_unlock_irq(&pool->lock);

- mutex_lock(&pool->manager_mutex);
+ mutex_lock(&pool->attach_mutex);
if (!list_empty(&pool->workers))
pool->detach_completion = &detach_completion;
- mutex_unlock(&pool->manager_mutex);
+ mutex_unlock(&pool->attach_mutex);

if (pool->detach_completion)
wait_for_completion(pool->detach_completion);
@@ -4513,11 +4513,11 @@ static void wq_unbind_fn(struct work_struct *work)
for_each_cpu_worker_pool(pool, cpu) {
WARN_ON_ONCE(cpu != smp_processor_id());

- mutex_lock(&pool->manager_mutex);
+ mutex_lock(&pool->attach_mutex);
spin_lock_irq(&pool->lock);

/*
- * We've blocked all manager operations. Make all workers
+ * We've blocked all attach/detach operations. Make all workers
* unbound and set DISASSOCIATED. Before this, all workers
* except for the ones which are still executing works from
* before the last CPU down must be on the cpu. After
@@ -4529,7 +4529,7 @@ static void wq_unbind_fn(struct work_struct *work)
pool->flags |= POOL_DISASSOCIATED;

spin_unlock_irq(&pool->lock);
- mutex_unlock(&pool->manager_mutex);
+ mutex_unlock(&pool->attach_mutex);

/*
* Call schedule() so that we cross rq->lock and thus can
@@ -4570,7 +4570,7 @@ static void rebind_workers(struct worker_pool *pool)
{
struct worker *worker;

- lockdep_assert_held(&pool->manager_mutex);
+ lockdep_assert_held(&pool->attach_mutex);

/*
* Restore CPU affinity of all workers. As all idle workers should
@@ -4638,7 +4638,7 @@ static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
static cpumask_t cpumask;
struct worker *worker;

- lockdep_assert_held(&pool->manager_mutex);
+ lockdep_assert_held(&pool->attach_mutex);

/* is @cpu allowed for @pool? */
if (!cpumask_test_cpu(cpu, pool->attrs->cpumask))
@@ -4683,7 +4683,7 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb,
mutex_lock(&wq_pool_mutex);

for_each_pool(pool, pi) {
- mutex_lock(&pool->manager_mutex);
+ mutex_lock(&pool->attach_mutex);

if (pool->cpu == cpu) {
spin_lock_irq(&pool->lock);
@@ -4695,7 +4695,7 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb,
restore_unbound_workers_cpumask(pool, cpu);
}

- mutex_unlock(&pool->manager_mutex);
+ mutex_unlock(&pool->attach_mutex);
}

/* update NUMA affinity of unbound workqueues */
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
index 8888e06..4521587 100644
--- a/kernel/workqueue_internal.h
+++ b/kernel/workqueue_internal.h
@@ -37,8 +37,8 @@ struct worker {
struct task_struct *task; /* I: worker task */
struct worker_pool *pool; /* I: the associated pool */
/* L: for rescuers */
- struct list_head node; /* M: anchored at pool->workers */
- /* M: runs through worker->node */
+ struct list_head node; /* A: anchored at pool->workers */
+ /* A: runs through worker->node */

unsigned long last_active; /* L: last active timestamp */
unsigned int flags; /* X: flags */
--
1.7.4.4