[PATCH 4.19 95/99] loop: Get rid of nested acquisition of loop_ctl_mutex

From: Greg Kroah-Hartman
Date: Mon Jan 21 2019 - 09:02:36 EST


4.19-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@xxxxxxx>

commit c28445fa06a3a54e06938559b9514c5a7f01c90f upstream.

The nested acquisition of loop_ctl_mutex (->lo_ctl_mutex back then) has
been introduced by commit f028f3b2f987e "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: Jan Kara <jack@xxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/block/loop.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -682,7 +682,7 @@ static int loop_change_fd(struct loop_de
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_devic
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_devic
{
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,
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 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_d
{
int err;

- err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+ err = mutex_lock_killable(&loop_ctl_mutex);
if (err)
return err;
switch (cmd) {