From 6060c07d476ebb1f21d28db5ba852e911246ce79 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Sun, 27 Oct 2019 15:01:43 -0700 Subject: [PATCH] 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: Davidlohr Bueso Signed-off-by: David Sterba --- fs/affs/affs.h | 16 ++++++++-------- fs/affs/super.c | 4 ++-- 2 files changed, 10 insertions(+), 10 deletions(-) diff --git a/fs/affs/affs.h b/fs/affs/affs.h index a92eb6ae2ae2..a755bef7c4c7 100644 --- a/fs/affs/affs.h +++ b/fs/affs/affs.h @@ -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); } diff --git a/fs/affs/super.c b/fs/affs/super.c index cc463ae47c12..9fcff55c65af 100644 --- a/fs/affs/super.c +++ b/fs/affs/super.c @@ -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); }