Commit fb199746 authored Apr 21, 2008 by Akinobu Mita Committed by Jens Axboe Apr 21, 2008

block: fix blk_register_queue() return value



blk_register_queue() returns -ENXIO when queue->request_fn is NULL.  But there
are some block drivers that call blk_register_queue() via add_disk() with
queue->request_fn == NULL.  (For example, brd, loop)

Although no one checks return value of blk_register_queue(), this patch makes
it return 0 instead of -ENXIO when queue->request_fn is NULL,

Also this patch adds warning when blk_register_queue() and
blk_unregister_queue() are called with queue == NULL rather than ignore
invalid usage silently.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

parent 2472892a

block/blk-sysfs.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -276,9 +276,12 @@ int blk_register_queue(struct gendisk *disk)

		struct request_queue *q = disk->queue;

		if (!q \|\| !q->request_fn)
		if (WARN_ON(!q))
		return -ENXIO;

		if (!q->request_fn)
		return 0;

		ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
		"%s", "queue");
		if (ret < 0)
		@@ -300,7 +303,10 @@ void blk_unregister_queue(struct gendisk *disk)
		{
		struct request_queue *q = disk->queue;

		if (q && q->request_fn) {
		if (WARN_ON(!q))
		return;

		if (q->request_fn) {
		elv_unregister_queue(q);

		kobject_uevent(&q->kobj, KOBJ_REMOVE);