fs: Convert bd_mount_sem to mutex

bd_mount_sem is used as mutex so make it a mutex.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>

fs/block_dev.c

@@ -240,7 +240,7 @@ struct super_block *freeze_bdev(struct block_device *bdev)
 	}
 	bdev->bd_fsfreeze_count++;
 
-	down(&bdev->bd_mount_sem);
+	mutex_lock(&bdev->bd_mount_sem);
 	sb = get_super(bdev);
 	if (sb && !(sb->s_flags & MS_RDONLY)) {
 		sb->s_frozen = SB_FREEZE_WRITE;
@@ -260,7 +260,7 @@ struct super_block *freeze_bdev(struct block_device *bdev)
 					"VFS:Filesystem freeze failed\n");
 				sb->s_frozen = SB_UNFROZEN;
 				drop_super(sb);
-				up(&bdev->bd_mount_sem);
+				mutex_unlock(&bdev->bd_mount_sem);
 				bdev->bd_fsfreeze_count--;
 				mutex_unlock(&bdev->bd_fsfreeze_mutex);
 				return ERR_PTR(error);
@@ -321,7 +321,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
 		drop_super(sb);
 	}
 
-	up(&bdev->bd_mount_sem);
+	mutex_unlock(&bdev->bd_mount_sem);
 	mutex_unlock(&bdev->bd_fsfreeze_mutex);
 	return 0;
 }
@@ -431,7 +431,7 @@ static void init_once(void *foo)
 
 	memset(bdev, 0, sizeof(*bdev));
 	mutex_init(&bdev->bd_mutex);
-	sema_init(&bdev->bd_mount_sem, 1);
+	mutex_init(&bdev->bd_mount_sem);
 	INIT_LIST_HEAD(&bdev->bd_inodes);
 	INIT_LIST_HEAD(&bdev->bd_list);
 #ifdef CONFIG_SYSFS

fs/super.c

@@ -740,9 +740,9 @@ int get_sb_bdev(struct file_system_type *fs_type,
 	 * will protect the lockfs code from trying to start a snapshot
 	 * while we are mounting
 	 */
-	down(&bdev->bd_mount_sem);
+	mutex_lock(&bdev->bd_mount_sem);
 	s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
-	up(&bdev->bd_mount_sem);
+	mutex_unlock(&bdev->bd_mount_sem);
 	if (IS_ERR(s))
 		goto error_s;
 

include/linux/fs.h

@@ -640,7 +640,7 @@ struct block_device {
 	struct super_block *	bd_super;
 	int			bd_openers;
 	struct mutex		bd_mutex;	/* open/close mutex */
-	struct semaphore	bd_mount_sem;
+	struct mutex		bd_mount_sem;
 	struct list_head	bd_inodes;
 	void *			bd_holder;
 	int			bd_holders;