> +static void blk_mq_resubmit_passthrough_io(struct request *rq)
> +{
> + struct request *nrq;
> + unsigned int flags = 0, cmd_flags = 0;
> + struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
> + struct blk_mq_tags *tags = rq->q->elevator ? hctx->sched_tags :
> + hctx->tags;
> + bool reserved = blk_mq_tag_is_reserved(tags, rq->internal_tag);
> +
> + if (rq->rq_flags & RQF_PREEMPT)
> + flags |= BLK_MQ_REQ_PREEMPT;
> + if (reserved)
> + flags |= BLK_MQ_REQ_RESERVED;
> +
> + /* avoid allocation failure & IO merge */
> + cmd_flags = (rq->cmd_flags & ~REQ_NOWAIT) | REQ_NOMERGE;
> +
> + nrq = blk_get_request(rq->q, cmd_flags, flags);
> + if (!nrq)
> + return;
> +
> + nrq->__sector = blk_rq_pos(rq);
> + nrq->__data_len = blk_rq_bytes(rq);
> + if (rq->rq_flags & RQF_SPECIAL_PAYLOAD) {
> + nrq->rq_flags |= RQF_SPECIAL_PAYLOAD;
> + nrq->special_vec = rq->special_vec;
> + }
> +#if defined(CONFIG_BLK_DEV_INTEGRITY)
> + nrq->nr_integrity_segments = rq->nr_integrity_segments;
> +#endif
> + nrq->nr_phys_segments = rq->nr_phys_segments;
> + nrq->ioprio = rq->ioprio;
> + nrq->extra_len = rq->extra_len;
> + nrq->rq_disk = rq->rq_disk;
> + nrq->part = rq->part;
> + nrq->write_hint = rq->write_hint;
> + nrq->timeout = rq->timeout;
This should share code with blk_rq_prep_clone() using a helper.
Note that blk_rq_prep_clone seems to miss things like the
write_hint and timeout, which we should fix as well.
> +static void blk_mq_resubmit_fs_io(struct request *rq)
> +{
> + struct bio_list list;
> + struct bio *bio;
> +
> + bio_list_init(&list);
> + blk_steal_bios(&list, rq);
> +
> + while (true) {
> + bio = bio_list_pop(&list);
> + if (!bio)
> + break;
> +
> + generic_make_request(bio);
> + }
This could be simplified to:
while ((bio = bio_list_pop(&list)))
generic_make_request(bio);
but then again the generic_make_request seems weird. Do we need
actually need any of the checks in generic_make_request? Shouldn't
we call into blk_mq_make_request directly?
Then again I wonder why the passthrough case doesn't work for
FS requests?
> static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
> {
> @@ -2394,14 +2482,38 @@ static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
> }
> spin_unlock(&ctx->lock);
>
> + if (!test_bit(BLK_MQ_S_INACTIVE, &hctx->state)) {
> + if (!list_empty(&tmp)) {
> + spin_lock(&hctx->lock);
> + list_splice_tail_init(&tmp, &hctx->dispatch);
> + spin_unlock(&hctx->lock);
> + blk_mq_run_hw_queue(hctx, true);
> + }
> + } else {
What about an early return or two here to save a level of indentation
later?
if (!test_bit(BLK_MQ_S_INACTIVE, &hctx->state)) {
if (list_empty(&tmp))
return 0;
spin_lock(&hctx->lock);
list_splice_tail_init(&tmp, &hctx->dispatch);
spin_unlock(&hctx->lock);
blk_mq_run_hw_queue(hctx, true);
return 0;
}
...
