From: Christoph Hellwig hch@lst.de
[ Upstream commit d2c7f56f8b5256d57f9e3fc7794c31361d43bdd9 ]
Ensure that the lo_device which is stored in the gendisk private data is valid until the gendisk is freed. Currently the loop driver uses a lot of effort to make sure a device is not freed when it is still in use, but to to fix a potential deadlock this will be relaxed a bit soon.
Signed-off-by: Christoph Hellwig hch@lst.de Reviewed-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20220330052917.2566582-12-hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/loop.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index a58595f5ee2c..ed7bec11948c 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1768,6 +1768,14 @@ static void lo_release(struct gendisk *disk, fmode_t mode) mutex_unlock(&lo->lo_mutex); }
+static void lo_free_disk(struct gendisk *disk) +{ + struct loop_device *lo = disk->private_data; + + mutex_destroy(&lo->lo_mutex); + kfree(lo); +} + static const struct block_device_operations lo_fops = { .owner = THIS_MODULE, .open = lo_open, @@ -1776,6 +1784,7 @@ static const struct block_device_operations lo_fops = { #ifdef CONFIG_COMPAT .compat_ioctl = lo_compat_ioctl, #endif + .free_disk = lo_free_disk, };
/* @@ -2090,15 +2099,14 @@ static void loop_remove(struct loop_device *lo) { /* Make this loop device unreachable from pathname. */ del_gendisk(lo->lo_disk); - blk_cleanup_disk(lo->lo_disk); + blk_cleanup_queue(lo->lo_disk->queue); blk_mq_free_tag_set(&lo->tag_set);
mutex_lock(&loop_ctl_mutex); idr_remove(&loop_index_idr, lo->lo_number); mutex_unlock(&loop_ctl_mutex); - /* There is no route which can find this loop device. */ - mutex_destroy(&lo->lo_mutex); - kfree(lo); + + put_disk(lo->lo_disk); }
static void loop_probe(dev_t dev)