Commit 958229a7 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: add a flag to make put_disk on partially initalized disks safer 



Add a flag to indicate that __device_add_disk did grab a queue reference
so that disk_release only drops it if we actually had it.  This sort
out one of the major pitfals with partially initialized gendisk that
a lot of drivers did get wrong or still do.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-5-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0d1feb72

block/genhd.c

+5 −2
Original line number Diff line number Diff line
@@ -539,7 +539,10 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk, 
	 * Take an extra ref on queue which will be put on disk_release()

	 * so that it sticks around as long as @disk is there.

	 */

	WARN_ON_ONCE(!blk_get_queue(disk->queue));

	if (blk_get_queue(disk->queue))

		set_bit(GD_QUEUE_REF, &disk->state);

	else

		WARN_ON_ONCE(1);



	disk_add_events(disk);

	blk_integrity_add(disk);
@@ -1107,7 +1110,7 @@ static void disk_release(struct device *dev) 
	kfree(disk->random);

	xa_destroy(&disk->part_tbl);

	bdput(disk->part0);

	if (disk->queue)

	if (test_bit(GD_QUEUE_REF, &disk->state) && disk->queue)

		blk_put_queue(disk->queue);

	kfree(disk);

}

include/linux/genhd.h

+1 −0
Original line number Diff line number Diff line
@@ -153,6 +153,7 @@ struct gendisk { 
	unsigned long state;

#define GD_NEED_PART_SCAN		0

#define GD_READ_ONLY			1

#define GD_QUEUE_REF			2

	struct kobject *slave_dir;



	struct timer_rand_state *random;