From ab96de5def854d8fc51280b6a20597e64b14ac31 Mon Sep 17 00:00:00 2001 From: Chaitanya Kulkarni Date: Thu, 6 May 2021 18:51:36 -0700 Subject: nvmet: fix inline bio check for passthru When handling passthru commands, for inline bio allocation we only consider the transfer size. This works well when req->sg_cnt fits into the req->inline_bvec, but it will result in the early return from bio_add_hw_page() when req->sg_cnt > NVMET_MAX_INLINE_BVEC. Consider an I/O of size 32768 and first buffer is not aligned to the page boundary, then I/O is split in following manner :- [ 2206.256140] nvmet: sg->length 3440 sg->offset 656 [ 2206.256144] nvmet: sg->length 4096 sg->offset 0 [ 2206.256148] nvmet: sg->length 4096 sg->offset 0 [ 2206.256152] nvmet: sg->length 4096 sg->offset 0 [ 2206.256155] nvmet: sg->length 4096 sg->offset 0 [ 2206.256159] nvmet: sg->length 4096 sg->offset 0 [ 2206.256163] nvmet: sg->length 4096 sg->offset 0 [ 2206.256166] nvmet: sg->length 4096 sg->offset 0 [ 2206.256170] nvmet: sg->length 656 sg->offset 0 Now the req->transfer_size == NVMET_MAX_INLINE_DATA_LEN i.e. 32768, but the req->sg_cnt is (9) > NVMET_MAX_INLINE_BIOVEC which is (8). This will result in early return in the following code path :- nvmet_bdev_execute_rw() bio_add_pc_page() bio_add_hw_page() if (bio_full(bio, len)) return 0; Use previously introduced helper nvmet_use_inline_bvec() to consider req->sg_cnt when using inline bio. This only affects nvme-loop transport. Fixes: dab3902b19a0 ("nvmet: use inline bio for passthru fast path") Signed-off-by: Chaitanya Kulkarni Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig --- drivers/nvme/target/passthru.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/nvme/target') diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c index 2798944899b7..39b1473f7204 100644 --- a/drivers/nvme/target/passthru.c +++ b/drivers/nvme/target/passthru.c @@ -194,7 +194,7 @@ static int nvmet_passthru_map_sg(struct nvmet_req *req, struct request *rq) if (req->sg_cnt > BIO_MAX_VECS) return -EINVAL; - if (req->transfer_len <= NVMET_MAX_INLINE_DATA_LEN) { + if (nvmet_use_inline_bvec(req)) { bio = &req->p.inline_bio; bio_init(bio, req->inline_bvec, ARRAY_SIZE(req->inline_bvec)); } else { -- cgit v1.2.3-59-g8ed1b