On 5/14/21 11:16 AM, Yiyuan GUO wrote:
> In function blk_mq_map_queues, qmap->nr_queues may equal zero
> and thus it needs to be checked before we pass it to function
> queue_index.
>
> Signed-off-by: Yiyuan GUO <yguoaz@xxxxxxxxxx>
> ---
> block/blk-mq-cpumap.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
> index 3db84d319..dc440870e 100644
> --- a/block/blk-mq-cpumap.c
> +++ b/block/blk-mq-cpumap.c
> @@ -65,7 +65,8 @@ int blk_mq_map_queues(struct blk_mq_queue_map *qmap)
> } else {
> first_sibling = get_first_sibling(cpu);
> if (first_sibling == cpu)
> - map[cpu] = queue_index(qmap, nr_queues, q++);
> + if (nr_queues)
> + map[cpu] = queue_index(qmap, nr_queues, q++);
> else
> map[cpu] = map[first_sibling];
> }
>
Err ... and what is the value of 'map[cpu]' if 'nr_queues' equals zero?
Please move the 'if (nr_queues)' condition into the first if-clause:
if ((first_sibling == cpu) && nr_queues)
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions Germany GmbH, 90409 Nürnberg
GF: F. Imendörffer, HRB 36809 (AG Nürnberg)
