From 9d2c70986bb7838c1c441a93bda415eecb52f3dd Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Tue, 22 Sep 2026 10:27:11 -0700 Subject: [PATCH] blk-mq: allow cached requests to be used for flush operations The cached request lookups reject a request whose op_is_flush() state does not match the incoming operation. That check is from when rq->elv and rq->flush shared a union, so a request could not be both a scheduler request and carry flush state. Commit be4c427809b0 ("blk-mq: use the I/O scheduler for writes from the flush state machine") made them separate members of struct request. A cached request now gets its scheduler state when it is claimed by an operation, so one claimed for a flush is set up exactly as a freshly allocated request. Drop the check so a cached batch can mix flush and non-flush operations. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Link: https://patch.msgid.link/20260922172711.1573186-2-kbusch@meta.com Signed-off-by: Jens Axboe --- block/blk-mq.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 5df6d2244db8..025a799f35b9 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -661,8 +661,6 @@ static struct request *blk_mq_alloc_cached_request(struct request_queue *q, if (blk_mq_get_hctx_type(opf) != rq->mq_hctx->type) return NULL; - if (op_is_flush(rq->cmd_flags) != op_is_flush(opf)) - return NULL; rq_list_pop(&plug->cached_rqs); rq->cmd_flags = opf; @@ -3075,8 +3073,6 @@ static struct request *blk_mq_get_cached_request(struct blk_plug *plug, if (type != rq->mq_hctx->type && (type != HCTX_TYPE_READ || rq->mq_hctx->type != HCTX_TYPE_DEFAULT)) return NULL; - if (op_is_flush(rq->cmd_flags) != op_is_flush(opf)) - return NULL; rq_list_pop(&plug->cached_rqs); return rq; }