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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jan Kara <jack@suse.cz>,
        Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 4.19 95/99] loop: Get rid of nested acquisition of loop_ctl_mutex
Date:   Mon, 21 Jan 2019 14:49:27 +0100
Message-Id: <20190121134919.547083403@linuxfoundation.org>
In-Reply-To: <20190121134913.924726465@linuxfoundation.org>
References: <20190121134913.924726465@linuxfoundation.org>
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4.19-stable review patch.  If anyone has any objections, please let me know.

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

From: Jan Kara <jack@suse.cz>

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@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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) {