Commit 3c1c875d authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm bufio: conditionally enable branching for DM_BUFIO_CLIENT_NO_SLEEP 



Use jump_label to limit the need for branching unless the optional
DM_BUFIO_CLIENT_NO_SLEEP is used.

Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent df326e7a

drivers/md/dm-bufio.c

+11 −4
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/module.h>

#include <linux/rbtree.h>

#include <linux/stacktrace.h>

#include <linux/jump_label.h>



#define DM_MSG_PREFIX "bufio"
@@ -164,13 +165,15 @@ struct dm_buffer { 
#endif

};



static DEFINE_STATIC_KEY_FALSE(no_sleep_enabled);



/*----------------------------------------------------------------*/



#define dm_bufio_in_request()	(!!current->bio_list)



static void dm_bufio_lock(struct dm_bufio_client *c)

{

	if (c->no_sleep)

	if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep)

		spin_lock_irqsave_nested(&c->spinlock, c->spinlock_flags, dm_bufio_in_request());

	else

		mutex_lock_nested(&c->lock, dm_bufio_in_request());
@@ -178,7 +181,7 @@ static void dm_bufio_lock(struct dm_bufio_client *c) 


static int dm_bufio_trylock(struct dm_bufio_client *c)

{

	if (c->no_sleep)

	if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep)

		return spin_trylock_irqsave(&c->spinlock, c->spinlock_flags);

	else

		return mutex_trylock(&c->lock);
@@ -186,7 +189,7 @@ static int dm_bufio_trylock(struct dm_bufio_client *c) 


static void dm_bufio_unlock(struct dm_bufio_client *c)

{

	if (c->no_sleep)

	if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep)

		spin_unlock_irqrestore(&c->spinlock, c->spinlock_flags);

	else

		mutex_unlock(&c->lock);
@@ -1760,8 +1763,10 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign 
	c->alloc_callback = alloc_callback;

	c->write_callback = write_callback;



	if (flags & DM_BUFIO_CLIENT_NO_SLEEP)

	if (flags & DM_BUFIO_CLIENT_NO_SLEEP) {

		c->no_sleep = true;

		static_branch_inc(&no_sleep_enabled);

	}



	for (i = 0; i < LIST_SIZE; i++) {

		INIT_LIST_HEAD(&c->lru[i]);
@@ -1895,6 +1900,8 @@ void dm_bufio_client_destroy(struct dm_bufio_client *c) 
	kmem_cache_destroy(c->slab_buffer);

	dm_io_client_destroy(c->dm_io);

	mutex_destroy(&c->lock);

	if (c->no_sleep)

		static_branch_dec(&no_sleep_enabled);

	kfree(c);

}

EXPORT_SYMBOL_GPL(dm_bufio_client_destroy);