On Wed, 2018-04-25 at 04:01 +0800, Ming Lei wrote:
> This reverts commit 37c7c6c76d431dd7ef9c29d95f6052bd425f004c.
>
> Turns out some drivers(most are FC drivers) may not use managed
> IRQ affinity, and has their customized .map_queues meantime, so
> still keep this code for avoiding regression.
>
> Reported-by: Laurence Oberman <loberman@xxxxxxxxxx>
> Cc: Ewan Milne <emilne@xxxxxxxxxx>
> Cc: Stefan Haberland <sth@xxxxxxxxxxxxxxxxxx>
> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> block/blk-mq.c | 34 +++++++++++++++++++++++++++++++---
> 1 file changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index e39276852638..f4891b792d0d 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2407,7 +2407,7 @@ static void blk_mq_free_map_and_requests(struct
> blk_mq_tag_set *set,
>
> static void blk_mq_map_swqueue(struct request_queue *q)
> {
> - unsigned int i;
> + unsigned int i, hctx_idx;
> struct blk_mq_hw_ctx *hctx;
> struct blk_mq_ctx *ctx;
> struct blk_mq_tag_set *set = q->tag_set;
> @@ -2424,8 +2424,23 @@ static void blk_mq_map_swqueue(struct
> request_queue *q)
>
> /*
> * Map software to hardware queues.
> + *
> + * If the cpu isn't present, the cpu is mapped to first
> hctx.
> */
> for_each_possible_cpu(i) {
> + hctx_idx = q->mq_map[i];
> + /* unmapped hw queue can be remapped after CPU topo
> changed */
> + if (!set->tags[hctx_idx] &&
> + !__blk_mq_alloc_rq_map(set, hctx_idx)) {
> + /*
> + * If tags initialization fail for some
> hctx,
> + * that hctx won't be brought online. In
> this
> + * case, remap the current ctx to hctx[0]
> which
> + * is guaranteed to always have tags
> allocated
> + */
> + q->mq_map[i] = 0;
> + }
> +
> ctx = per_cpu_ptr(q->queue_ctx, i);
> hctx = blk_mq_map_queue(q, i);
>
> @@ -2437,8 +2452,21 @@ static void blk_mq_map_swqueue(struct
> request_queue *q)
> mutex_unlock(&q->sysfs_lock);
>
> queue_for_each_hw_ctx(q, hctx, i) {
> - /* every hctx should get mapped by at least one CPU
> */
> - WARN_ON(!hctx->nr_ctx);
> + /*
> + * If no software queues are mapped to this hardware
> queue,
> + * disable it and free the request entries.
> + */
> + if (!hctx->nr_ctx) {
> + /* Never unmap queue 0. We need it as a
> + * fallback in case of a new remap fails
> + * allocation
> + */
> + if (i && set->tags[i])
> + blk_mq_free_map_and_requests(set,
> i);
> +
> + hctx->tags = NULL;
> + continue;
> + }
>
> hctx->tags = set->tags[i];
> WARN_ON(!hctx->tags);
Hello Ming
Thanks for getting this fixed so quickly.
The dumpstack is gone now of course.
Tested-by: Laurence Oberman <loberman@xxxxxxxxxx>
