From: Omar Sandoval <osandov@osandov.com>
To: linux-block@vger.kernel.org
Cc: Jens Axboe <axboe@fb.com>,
kernel-team@fb.com, linux-fsdevel@vger.kernel.org
Subject: [PATCH 2/2] loop: use interruptible lock in ioctls
Date: Mon, 26 Mar 2018 16:16:26 -0700 [thread overview]
Message-ID: <7ec1489d2ca54e886713efe5beb6dd379c2279b6.1522106130.git.osandov@fb.com> (raw)
In-Reply-To: <cover.1522106130.git.osandov@fb.com>
In-Reply-To: <cover.1522106130.git.osandov@fb.com>
From: Omar Sandoval <osandov@fb.com>
Even after the previous patch to drop lo_ctl_mutex while calling
vfs_getattr(), there are other cases where we can end up sleeping for a
long time while holding lo_ctl_mutex. Let's avoid the uninterruptible
sleep from the ioctls.
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
drivers/block/loop.c | 29 +++++++++++++++++++----------
1 file changed, 19 insertions(+), 10 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 93a60bda7608..28673cfdd3a3 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1360,7 +1360,10 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
struct loop_device *lo = bdev->bd_disk->private_data;
int err;
- mutex_lock_nested(&lo->lo_ctl_mutex, 1);
+ err = mutex_lock_interruptible_nested(&lo->lo_ctl_mutex, 1);
+ if (err)
+ goto out_unlocked;
+
switch (cmd) {
case LOOP_SET_FD:
err = loop_set_fd(lo, mode, bdev, arg);
@@ -1545,16 +1548,20 @@ static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
switch(cmd) {
case LOOP_SET_STATUS:
- mutex_lock(&lo->lo_ctl_mutex);
- err = loop_set_status_compat(
- lo, (const struct compat_loop_info __user *) arg);
- mutex_unlock(&lo->lo_ctl_mutex);
+ err = mutex_lock_interruptible(&lo->lo_ctl_mutex);
+ if (!err) {
+ err = loop_set_status_compat(lo,
+ (const struct compat_loop_info __user *)arg);
+ mutex_unlock(&lo->lo_ctl_mutex);
+ }
break;
case LOOP_GET_STATUS:
- mutex_lock(&lo->lo_ctl_mutex);
- err = loop_get_status_compat(
- lo, (struct compat_loop_info __user *) arg);
- /* loop_get_status() unlocks lo_ctl_mutex */
+ err = mutex_lock_interruptible(&lo->lo_ctl_mutex);
+ if (!err) {
+ err = loop_get_status_compat(lo,
+ (struct compat_loop_info __user *)arg);
+ /* loop_get_status() unlocks lo_ctl_mutex */
+ }
break;
case LOOP_SET_CAPACITY:
case LOOP_CLR_FD:
@@ -1959,7 +1966,9 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
ret = loop_lookup(&lo, parm);
if (ret < 0)
break;
- mutex_lock(&lo->lo_ctl_mutex);
+ ret = mutex_lock_interruptible(&lo->lo_ctl_mutex);
+ if (ret)
+ break;
if (lo->lo_state != Lo_unbound) {
ret = -EBUSY;
mutex_unlock(&lo->lo_ctl_mutex);
--
2.16.2
next prev parent reply other threads:[~2018-03-26 23:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-26 23:16 [PATCH 0/2] loop: don't hang on lo_ctl_mutex in ioctls Omar Sandoval
2018-03-26 23:16 ` [PATCH 1/2] loop: don't call into filesystem while holding lo_ctl_mutex Omar Sandoval
2018-03-26 23:16 ` Omar Sandoval [this message]
2018-03-27 0:04 ` [PATCH 2/2] loop: use interruptible lock in ioctls Matthew Wilcox
2018-03-27 4:35 ` Omar Sandoval
2018-03-28 13:18 ` David Sterba
2018-03-28 16:57 ` Matthew Wilcox
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7ec1489d2ca54e886713efe5beb6dd379c2279b6.1522106130.git.osandov@fb.com \
--to=osandov@osandov.com \
--cc=axboe@fb.com \
--cc=kernel-team@fb.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).