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Commit de6bf18e authored by Louis Rilling's avatar Louis Rilling Committed by Mark Fasheh
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[PATCH] configfs: Consolidate locking around configfs_detach_prep() in configfs_rmdir() 



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: default avatarLouis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: default avatarJoel Becker <Joel.Becker@oracle.com>
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent 9780eb6c

fs/configfs/dir.c

+7 −10
Original line number Diff line number Diff line
@@ -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);



		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);