Re: [patch] nbd: blk_mq_init_queue returns an error code on failure, not NULL
From: Omar Sandoval
Date: Mon Jan 09 2017 - 15:27:55 EST
On Mon, Jan 09, 2017 at 03:20:31PM -0500, Jeff Moyer wrote:
> Additionally, don't assign directly to disk->queue, otherwise
> blk_put_queue (called via put_disk) will choke (panic) on the errno
> stored there.
>
> Bug found by code inspection after Omar found a similar issue in
> virtio_blk. Compile-tested only.
>
> Signed-off-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Reviewed-by: Omar Sandoval <osandov@xxxxxx>
Compile-reviewed only :) Josef can probably test it if he cares enough,
but it looks right.
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 38c576f..50a2020 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -1042,6 +1042,7 @@ static int __init nbd_init(void)
> return -ENOMEM;
>
> for (i = 0; i < nbds_max; i++) {
> + struct request_queue *q;
> struct gendisk *disk = alloc_disk(1 << part_shift);
> if (!disk)
> goto out;
> @@ -1067,12 +1068,13 @@ static int __init nbd_init(void)
> * every gendisk to have its very own request_queue struct.
> * These structs are big so we dynamically allocate them.
> */
> - disk->queue = blk_mq_init_queue(&nbd_dev[i].tag_set);
> - if (!disk->queue) {
> + q = blk_mq_init_queue(&nbd_dev[i].tag_set);
> + if (IS_ERR(q)) {
> blk_mq_free_tag_set(&nbd_dev[i].tag_set);
> put_disk(disk);
> goto out;
> }
> + disk->queue = q;
>
> /*
> * Tell the block layer that we are not a rotational device