[PATCH 3/7] loop: don't hold lo->lo_mutex from __loop_clr_fd()
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: 2022-01-29 07:17:12
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
As a preparation for not holding lo->lo_mutex from lo_open()/lo_release() paths, move the updating of lo->lo_state in __loop_clr_fd() to callers. Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> --- drivers/block/loop.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 3a87c33df2ec..14b6f862531b 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c@@ -1100,11 +1100,9 @@ static void __loop_clr_fd(struct loop_device *lo, bool release) /* * Since this function is called upon "ioctl(LOOP_CLR_FD)" xor "close() * after ioctl(LOOP_CLR_FD)", it is a sign of something going wrong if - * lo->lo_state has changed while waiting for lo->lo_mutex. + * lo->lo_state has changed. */ - mutex_lock(&lo->lo_mutex); BUG_ON(lo->lo_state != Lo_rundown); - mutex_unlock(&lo->lo_mutex); if (test_bit(QUEUE_FLAG_WC, &lo->lo_queue->queue_flags)) blk_queue_write_cache(lo->lo_queue, false, false);
@@ -1167,18 +1165,9 @@ static void __loop_clr_fd(struct loop_device *lo, bool release) /* Device is gone, no point in returning error */ } - /* - * lo->lo_state is set to Lo_unbound here after above partscan has - * finished. There cannot be anybody else entering __loop_clr_fd() as - * Lo_rundown state protects us from all the other places trying to - * change the 'lo' device. - */ lo->lo_flags = 0; if (!part_shift) lo->lo_disk->flags |= GENHD_FL_NO_PART; - mutex_lock(&lo->lo_mutex); - lo->lo_state = Lo_unbound; - mutex_unlock(&lo->lo_mutex); /* Release backing file and unblock loop_exit(). */ fput(filp);
@@ -1215,6 +1204,10 @@ static int loop_clr_fd(struct loop_device *lo) mutex_unlock(&lo->lo_mutex); __loop_clr_fd(lo, false); + /* Allow loop_configure() to reuse this device. */ + mutex_lock(&lo->lo_mutex); + lo->lo_state = Lo_unbound; + mutex_unlock(&lo->lo_mutex); return 0; }
@@ -1740,6 +1733,9 @@ static void lo_release(struct gendisk *disk, fmode_t mode) * and remove configuration after last close. */ __loop_clr_fd(lo, true); + mutex_lock(&lo->lo_mutex); + lo->lo_state = Lo_unbound; + mutex_unlock(&lo->lo_mutex); return; } else if (lo->lo_state == Lo_bound) { /*
--
2.32.0