From 6060c07d476ebb1f21d28db5ba852e911246ce79 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Sun, 27 Oct 2019 15:01:43 -0700 Subject: [PATCH 1/2] 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); } From 450c3d4166837c496ebce03650c08800991f2150 Mon Sep 17 00:00:00 2001 From: Navid Emamdoost Date: Wed, 2 Oct 2019 16:52:37 -0500 Subject: [PATCH 2/2] affs: fix a memory leak in affs_remount In affs_remount if data is provided it is duplicated into new_opts. The allocated memory for new_opts is only released if parse_options fails. There's a bit of history behind new_options, originally there was save/replace options on the VFS layer so the 'data' passed must not change (thus strdup), this got cleaned up in later patches. But not completely. There's no reason to do the strdup in cases where the filesystem does not need to reuse the 'data' again, because strsep would modify it directly. Fixes: c8f33d0bec99 ("affs: kstrdup() memory handling") Signed-off-by: Navid Emamdoost [ update changelog ] Signed-off-by: David Sterba --- fs/affs/super.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/fs/affs/super.c b/fs/affs/super.c index 9fcff55c65af..47107c6712a6 100644 --- a/fs/affs/super.c +++ b/fs/affs/super.c @@ -561,14 +561,9 @@ affs_remount(struct super_block *sb, int *flags, char *data) int root_block; unsigned long mount_flags; int res = 0; - char *new_opts; char volume[32]; char *prefix = NULL; - new_opts = kstrdup(data, GFP_KERNEL); - if (data && !new_opts) - return -ENOMEM; - pr_debug("%s(flags=0x%x,opts=\"%s\")\n", __func__, *flags, data); sync_filesystem(sb); @@ -579,7 +574,6 @@ affs_remount(struct super_block *sb, int *flags, char *data) &blocksize, &prefix, volume, &mount_flags)) { kfree(prefix); - kfree(new_opts); return -EINVAL; }