From 32a7991b6a9c758e4e2b8166c5e1cc7563c3dcde Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 18 Jul 2012 20:43:19 +0400 Subject: [PATCH] tidy up namei.c a bit locking/unlocking for rcu walk taken to a couple of inline helpers Signed-off-by: Al Viro --- fs/namei.c | 39 +++++++++++++++++++++------------------ 1 file changed, 21 insertions(+), 18 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index d4d15bbc8af7..2ccc35c4dc24 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -427,6 +427,18 @@ EXPORT_SYMBOL(path_put); * to restart the path walk from the beginning in ref-walk mode. */ +static inline void lock_rcu_walk(void) +{ + br_read_lock(&vfsmount_lock); + rcu_read_lock(); +} + +static inline void unlock_rcu_walk(void) +{ + rcu_read_unlock(); + br_read_unlock(&vfsmount_lock); +} + /** * unlazy_walk - try to switch to ref-walk mode. * @nd: nameidata pathwalk data @@ -480,8 +492,7 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) } mntget(nd->path.mnt); - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); nd->flags &= ~LOOKUP_RCU; return 0; @@ -522,15 +533,13 @@ static int complete_walk(struct nameidata *nd) spin_lock(&dentry->d_lock); if (unlikely(!__d_rcu_to_refcount(dentry, nd->seq))) { spin_unlock(&dentry->d_lock); - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); return -ECHILD; } BUG_ON(nd->inode != dentry->d_inode); spin_unlock(&dentry->d_lock); mntget(nd->path.mnt); - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); } if (likely(!(nd->flags & LOOKUP_JUMPED))) @@ -985,8 +994,7 @@ failed: nd->flags &= ~LOOKUP_RCU; if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); return -ECHILD; } @@ -1323,8 +1331,7 @@ static void terminate_walk(struct nameidata *nd) nd->flags &= ~LOOKUP_RCU; if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); } } @@ -1691,8 +1698,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, nd->path = nd->root; nd->inode = inode; if (flags & LOOKUP_RCU) { - br_read_lock(&vfsmount_lock); - rcu_read_lock(); + lock_rcu_walk(); nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); } else { path_get(&nd->path); @@ -1704,8 +1710,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, if (*name=='/') { if (flags & LOOKUP_RCU) { - br_read_lock(&vfsmount_lock); - rcu_read_lock(); + lock_rcu_walk(); set_root_rcu(nd); } else { set_root(nd); @@ -1717,8 +1722,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, struct fs_struct *fs = current->fs; unsigned seq; - br_read_lock(&vfsmount_lock); - rcu_read_lock(); + lock_rcu_walk(); do { seq = read_seqcount_begin(&fs->seq); @@ -1753,8 +1757,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, if (fput_needed) *fp = file; nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); - br_read_lock(&vfsmount_lock); - rcu_read_lock(); + lock_rcu_walk(); } else { path_get(&file->f_path); fput_light(file, fput_needed); -- 2.20.1