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>
---
block/blk-sysfs.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
Index: 2.6-rc/block/blk-sysfs.c
===================================================================
--- 2.6-rc.orig/block/blk-sysfs.c
+++ 2.6-rc/block/blk-sysfs.c
@@ -276,9 +276,12 @@ int blk_register_queue(struct gendisk *d
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
{
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);
--
