loop: Get rid of 'nested' acquisition of loop_ctl_mutex

commit c28445fa upstream.

The nested acquisition of loop_ctl_mutex (->lo_ctl_mutex back then) has
been introduced by commit f028f3b2 "loop: fix circular locking in
loop_clr_fd()" to fix lockdep complains about bd_mutex being acquired
after lo_ctl_mutex during partition rereading. Now that these are
properly fixed, let's stop fooling lockdep.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/block/loop.c

@@ -682,7 +682,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 	int		error;
 	bool		partscan;
 
-	error = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+	error = mutex_lock_killable(&loop_ctl_mutex);
 	if (error)
 		return error;
 	error = -ENXIO;
@@ -920,7 +920,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
 	if (!file)
 		goto out;
 
-	error = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+	error = mutex_lock_killable(&loop_ctl_mutex);
 	if (error)
 		goto out_putf;
 
@@ -1136,7 +1136,7 @@ static int loop_clr_fd(struct loop_device *lo)
 {
 	int err;
 
-	err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+	err = mutex_lock_killable(&loop_ctl_mutex);
 	if (err)
 		return err;
 	if (lo->lo_state != Lo_bound) {
@@ -1173,7 +1173,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 	struct block_device *bdev;
 	bool partscan = false;
 
-	err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+	err = mutex_lock_killable(&loop_ctl_mutex);
 	if (err)
 		return err;
 	if (lo->lo_encrypt_key_size &&
@@ -1278,7 +1278,7 @@ loop_get_status(struct loop_device *lo, struct loop_info64 *info)
 	struct kstat stat;
 	int ret;
 
-	ret = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+	ret = mutex_lock_killable(&loop_ctl_mutex);
 	if (ret)
 		return ret;
 	if (lo->lo_state != Lo_bound) {
@@ -1467,7 +1467,7 @@ static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd,
 {
 	int err;
 
-	err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+	err = mutex_lock_killable(&loop_ctl_mutex);
 	if (err)
 		return err;
 	switch (cmd) {