It appears that configfs_rmdir() can protect configfs_detach_prep() retries with
less calls to {spin,mutex}_{lock,unlock}, and a cleaner code.

This patch does not change any behavior, except that it removes two useless
lock/unlock pairs having nothing inside to protect and providing a useless
barrier.

Signed-off-by: Louis Rilling
---
fs/configfs/dir.c | 17 +++++++----------
1 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 7a8db78..8e93341 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1311,16 +1311,18 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
* Ensure that no racing symlink() will make detach_prep() fail while
* the new link is temporarily attached
*/
- mutex_lock(&configfs_symlink_mutex);
- spin_lock(&configfs_dirent_lock);
do {
struct mutex *wait_mutex;

+ mutex_lock(&configfs_symlink_mutex);
+ spin_lock(&configfs_dirent_lock);
ret = configfs_detach_prep(dentry, &wait_mutex);
- if (ret) {
+ if (ret)
configfs_detach_rollback(dentry);
- spin_unlock(&configfs_dirent_lock);
- mutex_unlock(&configfs_symlink_mutex);
+ spin_unlock(&configfs_dirent_lock);
+ mutex_unlock(&configfs_symlink_mutex);
+
+ if (ret) {
if (ret != -EAGAIN) {
config_item_put(parent_item);
return ret;
@@ -1329,13 +1331,8 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
/* Wait until the racing operation terminates */
mutex_lock(wait_mutex);
mutex_unlock(wait_mutex);
-
- mutex_lock(&configfs_symlink_mutex);
- spin_lock(&configfs_dirent_lock);
}
} while (ret == -EAGAIN);
- spin_unlock(&configfs_dirent_lock);
- mutex_unlock(&configfs_symlink_mutex);

/* Get a working ref for the duration of this function */
item = configfs_get_config_item(dentry);
--
1.5.5.3

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