diff options
| -rw-r--r-- | block/blk-mq.c | 66 |
1 files changed, 40 insertions, 26 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 492aeda44da6..3e370f5bc40a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1255,18 +1255,50 @@ static void blk_mq_handle_zone_resource(struct request *rq, __blk_mq_requeue_request(rq); } +enum prep_dispatch { + PREP_DISPATCH_OK, + PREP_DISPATCH_NO_TAG, + PREP_DISPATCH_NO_BUDGET, +}; + +static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq, + bool need_budget) +{ + struct blk_mq_hw_ctx *hctx = rq->mq_hctx; + + if (need_budget && !blk_mq_get_dispatch_budget(rq->q)) { + blk_mq_put_driver_tag(rq); + return PREP_DISPATCH_NO_BUDGET; + } + + if (!blk_mq_get_driver_tag(rq)) { + /* + * The initial allocation attempt failed, so we need to + * rerun the hardware queue when a tag is freed. The + * waitqueue takes care of that. If the queue is run + * before we add this entry back on the dispatch list, + * we'll re-run it below. + */ + if (!blk_mq_mark_tag_wait(hctx, rq)) { + blk_mq_put_dispatch_budget(rq->q); + return PREP_DISPATCH_NO_TAG; + } + } + + return PREP_DISPATCH_OK; +} + /* * Returns true if we did some work AND can potentially do more. */ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, bool got_budget) { + enum prep_dispatch prep; struct request_queue *q = hctx->queue; struct request *rq, *nxt; - bool no_tag = false; int errors, queued; blk_status_t ret = BLK_STS_OK; - bool no_budget_avail = false; LIST_HEAD(zone_list); if (list_empty(list)) @@ -1284,31 +1316,9 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, rq = list_first_entry(list, struct request, queuelist); WARN_ON_ONCE(hctx != rq->mq_hctx); - if (!got_budget && !blk_mq_get_dispatch_budget(q)) { - blk_mq_put_driver_tag(rq); - no_budget_avail = true; + prep = blk_mq_prep_dispatch_rq(rq, !got_budget); + if (prep != PREP_DISPATCH_OK) break; - } - - if (!blk_mq_get_driver_tag(rq)) { - /* - * The initial allocation attempt failed, so we need to - * rerun the hardware queue when a tag is freed. The - * waitqueue takes care of that. If the queue is run - * before we add this entry back on the dispatch list, - * we'll re-run it below. - */ - if (!blk_mq_mark_tag_wait(hctx, rq)) { - blk_mq_put_dispatch_budget(q); - /* - * For non-shared tags, the RESTART check - * will suffice. - */ - if (hctx->flags & BLK_MQ_F_TAG_SHARED) - no_tag = true; - break; - } - } list_del_init(&rq->queuelist); @@ -1361,6 +1371,10 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, */ if (!list_empty(list)) { bool needs_restart; + /* For non-shared tags, the RESTART check will suffice */ + bool no_tag = prep == PREP_DISPATCH_NO_TAG && + (hctx->flags & BLK_MQ_F_TAG_SHARED); + bool no_budget_avail = prep == PREP_DISPATCH_NO_BUDGET; /* * If we didn't flush the entire list, we could have told |