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Commit b196be89 authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds
Browse files

workqueue: make alloc_workqueue() take printf fmt and args for name 



alloc_workqueue() currently expects the passed in @name pointer to remain
accessible.  This is inconvenient and a bit silly given that the whole wq
is being dynamically allocated.  This patch updates alloc_workqueue() and
friends to take printf format string instead of opaque string and matching
varargs at the end.  The name is allocated together with the wq and
formatted.

alloc_ordered_workqueue() is converted to a macro to unify varargs
handling with alloc_workqueue(), and, while at it, add comment to
alloc_workqueue().

None of the current in-kernel users pass in string with '%' as constant
name and this change shouldn't cause any problem.

[akpm@linux-foundation.org: use __printf]
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Suggested-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0499680a

include/linux/workqueue.h

+31 −16
Original line number Diff line number Diff line
@@ -297,32 +297,50 @@ extern struct workqueue_struct *system_unbound_wq; 
extern struct workqueue_struct *system_freezable_wq;



extern struct workqueue_struct *

__alloc_workqueue_key(const char *name, unsigned int flags, int max_active,

		      struct lock_class_key *key, const char *lock_name);

__alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,

	struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);



/**

 * alloc_workqueue - allocate a workqueue

 * @fmt: printf format for the name of the workqueue

 * @flags: WQ_* flags

 * @max_active: max in-flight work items, 0 for default

 * @args: args for @fmt

 *

 * Allocate a workqueue with the specified parameters.  For detailed

 * information on WQ_* flags, please refer to Documentation/workqueue.txt.

 *

 * The __lock_name macro dance is to guarantee that single lock_class_key

 * doesn't end up with different namesm, which isn't allowed by lockdep.

 *

 * RETURNS:

 * Pointer to the allocated workqueue on success, %NULL on failure.

 */

#ifdef CONFIG_LOCKDEP

#define alloc_workqueue(name, flags, max_active)		\

#define alloc_workqueue(fmt, flags, max_active, args...)	\

({								\

	static struct lock_class_key __key;			\

	const char *__lock_name;				\

								\

	if (__builtin_constant_p(name))				\

		__lock_name = (name);				\

	if (__builtin_constant_p(fmt))				\

		__lock_name = (fmt);				\

	else							\

		__lock_name = #name;				\

		__lock_name = #fmt;				\

								\

	__alloc_workqueue_key((name), (flags), (max_active),	\

			      &__key, __lock_name);		\

	__alloc_workqueue_key((fmt), (flags), (max_active),	\

			      &__key, __lock_name, ##args);	\

})

#else

#define alloc_workqueue(name, flags, max_active)		\

	__alloc_workqueue_key((name), (flags), (max_active), NULL, NULL)

#define alloc_workqueue(fmt, flags, max_active, args...)	\

	__alloc_workqueue_key((fmt), (flags), (max_active),	\

			      NULL, NULL, ##args)

#endif



/**

 * alloc_ordered_workqueue - allocate an ordered workqueue

 * @name: name of the workqueue

 * @fmt: printf format for the name of the workqueue

 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)

 * @args: args for @fmt

 *

 * Allocate an ordered workqueue.  An ordered workqueue executes at

 * most one work item at any given time in the queued order.  They are
@@ -331,11 +349,8 @@ __alloc_workqueue_key(const char *name, unsigned int flags, int max_active, 
 * RETURNS:

 * Pointer to the allocated workqueue on success, %NULL on failure.

 */

static inline struct workqueue_struct *

alloc_ordered_workqueue(const char *name, unsigned int flags)

{

	return alloc_workqueue(name, WQ_UNBOUND | flags, 1);

}

#define alloc_ordered_workqueue(fmt, flags, args...)		\

	alloc_workqueue(fmt, WQ_UNBOUND | (flags), 1, ##args)



#define create_workqueue(name)					\

	alloc_workqueue((name), WQ_MEM_RECLAIM, 1)

kernel/workqueue.c

+22 −10
Original line number Diff line number Diff line
@@ -242,10 +242,10 @@ struct workqueue_struct { 


	int			nr_drainers;	/* W: drain in progress */

	int			saved_max_active; /* W: saved cwq max_active */

	const char		*name;		/* I: workqueue name */

#ifdef CONFIG_LOCKDEP

	struct lockdep_map	lockdep_map;

#endif

	char			name[];		/* I: workqueue name */

};



struct workqueue_struct *system_wq __read_mostly;
@@ -2954,14 +2954,29 @@ static int wq_clamp_max_active(int max_active, unsigned int flags, 
	return clamp_val(max_active, 1, lim);

}



struct workqueue_struct *__alloc_workqueue_key(const char *name,

struct workqueue_struct *__alloc_workqueue_key(const char *fmt,

					       unsigned int flags,

					       int max_active,

					       struct lock_class_key *key,

					       const char *lock_name)

					       const char *lock_name, ...)

{

	va_list args, args1;

	struct workqueue_struct *wq;

	unsigned int cpu;

	size_t namelen;



	/* determine namelen, allocate wq and format name */

	va_start(args, lock_name);

	va_copy(args1, args);

	namelen = vsnprintf(NULL, 0, fmt, args) + 1;



	wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL);

	if (!wq)

		goto err;



	vsnprintf(wq->name, namelen, fmt, args1);

	va_end(args);

	va_end(args1);



	/*

	 * Workqueues which may be used during memory reclaim should
@@ -2978,12 +2993,9 @@ struct workqueue_struct *__alloc_workqueue_key(const char *name, 
		flags |= WQ_HIGHPRI;



	max_active = max_active ?: WQ_DFL_ACTIVE;

	max_active = wq_clamp_max_active(max_active, flags, name);



	wq = kzalloc(sizeof(*wq), GFP_KERNEL);

	if (!wq)

		goto err;

	max_active = wq_clamp_max_active(max_active, flags, wq->name);



	/* init wq */

	wq->flags = flags;

	wq->saved_max_active = max_active;

	mutex_init(&wq->flush_mutex);
@@ -2991,7 +3003,6 @@ struct workqueue_struct *__alloc_workqueue_key(const char *name, 
	INIT_LIST_HEAD(&wq->flusher_queue);

	INIT_LIST_HEAD(&wq->flusher_overflow);



	wq->name = name;

	lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);

	INIT_LIST_HEAD(&wq->list);
@@ -3020,7 +3031,8 @@ struct workqueue_struct *__alloc_workqueue_key(const char *name, 
		if (!rescuer)

			goto err;



		rescuer->task = kthread_create(rescuer_thread, wq, "%s", name);

		rescuer->task = kthread_create(rescuer_thread, wq, "%s",

					       wq->name);

		if (IS_ERR(rescuer->task))

			goto err;