From: Jan Kara <jack@suse.cz>
To: Jens Axboe <axboe@kernel.dk>
Cc: <linux-block@vger.kernel.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Jan Kara <jack@suse.cz>
Subject: [PATCH 05/16] loop: Push lo_ctl_mutex down into individual ioctls
Date: Thu, 8 Nov 2018 14:01:05 +0100 [thread overview]
Message-ID: <20181108130116.12140-6-jack@suse.cz> (raw)
In-Reply-To: <20181108130116.12140-1-jack@suse.cz>
Push acquisition of lo_ctl_mutex down into individual ioctl handling
branches. This is a preparatory step for pushing the lock down into
individual ioctl handling functions so that they can release the lock as
they need it. We also factor out some simple ioctl handlers that will
not need any special handling to reduce unnecessary code duplication.
Signed-off-by: Jan Kara <jack@suse.cz>
---
drivers/block/loop.c | 88 +++++++++++++++++++++++++++++++++++++---------------
1 file changed, 63 insertions(+), 25 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index dcdc96f4d2d4..4c37578989c4 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1393,70 +1393,108 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
return 0;
}
-static int lo_ioctl(struct block_device *bdev, fmode_t mode,
- unsigned int cmd, unsigned long arg)
+static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd,
+ unsigned long arg)
{
- struct loop_device *lo = bdev->bd_disk->private_data;
int err;
err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
if (err)
- goto out_unlocked;
+ return err;
+ switch (cmd) {
+ case LOOP_SET_CAPACITY:
+ err = loop_set_capacity(lo);
+ break;
+ case LOOP_SET_DIRECT_IO:
+ err = loop_set_dio(lo, arg);
+ break;
+ case LOOP_SET_BLOCK_SIZE:
+ err = loop_set_block_size(lo, arg);
+ break;
+ default:
+ err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
+ }
+ mutex_unlock(&loop_ctl_mutex);
+ return err;
+}
+
+static int lo_ioctl(struct block_device *bdev, fmode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ struct loop_device *lo = bdev->bd_disk->private_data;
+ int err;
switch (cmd) {
case LOOP_SET_FD:
+ err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+ if (err)
+ return err;
err = loop_set_fd(lo, mode, bdev, arg);
+ mutex_unlock(&loop_ctl_mutex);
break;
case LOOP_CHANGE_FD:
+ err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+ if (err)
+ return err;
err = loop_change_fd(lo, bdev, arg);
+ mutex_unlock(&loop_ctl_mutex);
break;
case LOOP_CLR_FD:
+ err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+ if (err)
+ return err;
/* loop_clr_fd would have unlocked loop_ctl_mutex on success */
err = loop_clr_fd(lo);
- if (!err)
- goto out_unlocked;
+ if (err)
+ mutex_unlock(&loop_ctl_mutex);
break;
case LOOP_SET_STATUS:
err = -EPERM;
- if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
+ if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
+ err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+ if (err)
+ return err;
err = loop_set_status_old(lo,
(struct loop_info __user *)arg);
+ mutex_unlock(&loop_ctl_mutex);
+ }
break;
case LOOP_GET_STATUS:
+ err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+ if (err)
+ return err;
err = loop_get_status_old(lo, (struct loop_info __user *) arg);
/* loop_get_status() unlocks loop_ctl_mutex */
- goto out_unlocked;
+ break;
case LOOP_SET_STATUS64:
err = -EPERM;
- if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
+ if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
+ err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+ if (err)
+ return err;
err = loop_set_status64(lo,
(struct loop_info64 __user *) arg);
+ mutex_unlock(&loop_ctl_mutex);
+ }
break;
case LOOP_GET_STATUS64:
+ err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+ if (err)
+ return err;
err = loop_get_status64(lo, (struct loop_info64 __user *) arg);
/* loop_get_status() unlocks loop_ctl_mutex */
- goto out_unlocked;
- case LOOP_SET_CAPACITY:
- err = -EPERM;
- if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
- err = loop_set_capacity(lo);
break;
+ case LOOP_SET_CAPACITY:
case LOOP_SET_DIRECT_IO:
- err = -EPERM;
- if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
- err = loop_set_dio(lo, arg);
- break;
case LOOP_SET_BLOCK_SIZE:
- err = -EPERM;
- if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
- err = loop_set_block_size(lo, arg);
- break;
+ if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ /* Fall through */
default:
- err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
+ err = lo_simple_ioctl(lo, cmd, arg);
+ break;
}
- mutex_unlock(&loop_ctl_mutex);
-out_unlocked:
return err;
}
--
2.16.4
next prev parent reply other threads:[~2018-11-08 13:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-08 13:01 [PATCH 0/16 v3] loop: Fix oops and possible deadlocks Jan Kara
2018-11-08 13:01 ` [PATCH 01/16] block/loop: Don't grab "struct file" for vfs_getattr() operation Jan Kara
2018-11-08 13:01 ` [PATCH 02/16] block/loop: Use global lock for ioctl() operation Jan Kara
2018-11-08 13:01 ` [PATCH 03/16] loop: Fold __loop_release into loop_release Jan Kara
2018-11-08 13:01 ` [PATCH 04/16] loop: Get rid of loop_index_mutex Jan Kara
2018-11-08 13:01 ` Jan Kara [this message]
2018-11-08 13:01 ` [PATCH 06/16] loop: Split setting of lo_state from loop_clr_fd Jan Kara
2018-11-08 13:01 ` [PATCH 07/16] loop: Push loop_ctl_mutex down into loop_clr_fd() Jan Kara
2018-11-08 13:01 ` [PATCH 08/16] loop: Push loop_ctl_mutex down to loop_get_status() Jan Kara
2018-11-08 13:01 ` [PATCH 09/16] loop: Push loop_ctl_mutex down to loop_set_status() Jan Kara
2018-11-08 13:01 ` [PATCH 10/16] loop: Push loop_ctl_mutex down to loop_set_fd() Jan Kara
2018-11-08 13:01 ` [PATCH 11/16] loop: Push loop_ctl_mutex down to loop_change_fd() Jan Kara
2018-11-08 13:01 ` [PATCH 12/16] loop: Move special partition reread handling in loop_clr_fd() Jan Kara
2018-11-08 13:01 ` [PATCH 13/16] loop: Move loop_reread_partitions() out of loop_ctl_mutex Jan Kara
2018-11-08 13:01 ` [PATCH 14/16] loop: Fix deadlock when calling blkdev_reread_part() Jan Kara
2018-11-08 13:01 ` [PATCH 15/16] loop: Avoid circular locking dependency between loop_ctl_mutex and bd_mutex Jan Kara
2018-11-08 13:01 ` [PATCH 16/16] loop: Get rid of 'nested' acquisition of loop_ctl_mutex Jan Kara
2018-11-08 13:21 ` [PATCH 0/16 v3] loop: Fix oops and possible deadlocks Jens Axboe
2018-11-08 13:25 ` Jan Kara
2018-11-08 13:31 ` Jens Axboe
2018-11-08 21:28 ` Theodore Y. Ts'o
2018-11-12 10:15 ` Jan Kara
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