Commit 6060c07d authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by David Sterba
Browse files

affs: Replace binary semaphores with mutexes 



At a slight footprint cost (24 vs 32 bytes), mutexes are more optimal
than semaphores; it's also a nicer interface for mutual exclusion,
which is why they are encouraged over binary semaphores, when possible.

For both i_link_lock and i_ext_lock (and hence i_hash_lock which I
annotated for the hash lock mapping hackery for lockdep), their semantics
imply traditional lock ownership; that is, the lock owner is the same for
both lock/unlock operations and does not run in irq context. Therefore
it is safe to convert.

Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent af42d346

fs/affs/affs.h

+8 −8
Original line number Diff line number Diff line
@@ -43,8 +43,8 @@ struct affs_ext_key { 
 */

struct affs_inode_info {

	atomic_t i_opencnt;

	struct semaphore i_link_lock;		/* Protects internal inode access. */

	struct semaphore i_ext_lock;		/* Protects internal inode access. */

	struct mutex i_link_lock;		/* Protects internal inode access. */

	struct mutex i_ext_lock;		/* Protects internal inode access. */

#define i_hash_lock i_ext_lock

	u32	 i_blkcnt;			/* block count */

	u32	 i_extcnt;			/* extended block count */
@@ -293,30 +293,30 @@ affs_adjust_bitmapchecksum(struct buffer_head *bh, u32 val) 
static inline void

affs_lock_link(struct inode *inode)

{

	down(&AFFS_I(inode)->i_link_lock);

	mutex_lock(&AFFS_I(inode)->i_link_lock);

}

static inline void

affs_unlock_link(struct inode *inode)

{

	up(&AFFS_I(inode)->i_link_lock);

	mutex_unlock(&AFFS_I(inode)->i_link_lock);

}

static inline void

affs_lock_dir(struct inode *inode)

{

	down(&AFFS_I(inode)->i_hash_lock);

	mutex_lock_nested(&AFFS_I(inode)->i_hash_lock, SINGLE_DEPTH_NESTING);

}

static inline void

affs_unlock_dir(struct inode *inode)

{

	up(&AFFS_I(inode)->i_hash_lock);

	mutex_unlock(&AFFS_I(inode)->i_hash_lock);

}

static inline void

affs_lock_ext(struct inode *inode)

{

	down(&AFFS_I(inode)->i_ext_lock);

	mutex_lock(&AFFS_I(inode)->i_ext_lock);

}

static inline void

affs_unlock_ext(struct inode *inode)

{

	up(&AFFS_I(inode)->i_ext_lock);

	mutex_unlock(&AFFS_I(inode)->i_ext_lock);

}

fs/affs/super.c

+2 −2
Original line number Diff line number Diff line
@@ -121,8 +121,8 @@ static void init_once(void *foo) 
{

	struct affs_inode_info *ei = (struct affs_inode_info *) foo;



	sema_init(&ei->i_link_lock, 1);

	sema_init(&ei->i_ext_lock, 1);

	mutex_init(&ei->i_link_lock);

	mutex_init(&ei->i_ext_lock);

	inode_init_once(&ei->vfs_inode);

}

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