struct request_queue *q = hctx->queue;
struct elevator_queue *e = q->elevator;
const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request;
- bool did_work = false;
+ bool do_sched_dispatch = true;
LIST_HEAD(rq_list);
/* RCU or SRCU read lock is needed before checking quiesced flag */
*/
if (!list_empty(&rq_list)) {
blk_mq_sched_mark_restart_hctx(hctx);
- did_work = blk_mq_dispatch_rq_list(q, &rq_list);
+ do_sched_dispatch = blk_mq_dispatch_rq_list(q, &rq_list);
} else if (!has_sched_dispatch) {
blk_mq_flush_busy_ctxs(hctx, &rq_list);
blk_mq_dispatch_rq_list(q, &rq_list);
}
/*
- * We want to dispatch from the scheduler if we had no work left
- * on the dispatch list, OR if we did have work but weren't able
- * to make progress.
+ * We want to dispatch from the scheduler if there was nothing
+ * on the dispatch list or we were able to dispatch from the
+ * dispatch list.
*/
- if (!did_work && has_sched_dispatch) {
+ if (do_sched_dispatch && has_sched_dispatch) {
do {
struct request *rq;
return e->type->ops.mq.bio_merge(hctx, bio);
}
- if (hctx->flags & BLK_MQ_F_SHOULD_MERGE) {
+ if ((hctx->flags & BLK_MQ_F_SHOULD_MERGE) &&
+ !list_empty_careful(&ctx->rq_list)) {
/* default per sw-queue merge */
spin_lock(&ctx->lock);
ret = blk_mq_attempt_merge(q, ctx, bio);