From: Chaitanya Kulkarni chaitanya.kulkarni@wdc.com
[ Upstream commit 608a969046e6e0567d05a166be66c77d2dd8220b ]
When handling rw commands, for inline bio case we only consider transfer size. This works well when req->sg_cnt fits into the req->inline_bvec, but it will result in the warning in __bio_add_page() when req->sg_cnt > NVMET_MAX_INLINE_BVEC.
Consider an I/O size 32768 and first page 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 the following warning message :-
nvmet_bdev_execute_rw() bio_add_page() __bio_add_page() WARN_ON_ONCE(bio_full(bio, len));
This scenario is very hard to reproduce on the nvme-loop transport only with rw commands issued with the passthru IOCTL interface from the host application and the data buffer is allocated with the malloc() and not the posix_memalign().
Fixes: 73383adfad24 ("nvmet: don't split large I/Os unconditionally") Signed-off-by: Chaitanya Kulkarni chaitanya.kulkarni@wdc.com Reviewed-by: Sagi Grimberg sagi@grimberg.me Signed-off-by: Christoph Hellwig hch@lst.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvme/target/io-cmd-bdev.c | 2 +- drivers/nvme/target/nvmet.h | 6 ++++++ 2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c index 23095bdfce06..6a9626ff0713 100644 --- a/drivers/nvme/target/io-cmd-bdev.c +++ b/drivers/nvme/target/io-cmd-bdev.c @@ -258,7 +258,7 @@ static void nvmet_bdev_execute_rw(struct nvmet_req *req)
sector = nvmet_lba_to_sect(req->ns, req->cmd->rw.slba);
- if (req->transfer_len <= NVMET_MAX_INLINE_DATA_LEN) { + if (nvmet_use_inline_bvec(req)) { bio = &req->b.inline_bio; bio_init(bio, req->inline_bvec, ARRAY_SIZE(req->inline_bvec)); } else { diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h index c585f4152535..bc91336080e0 100644 --- a/drivers/nvme/target/nvmet.h +++ b/drivers/nvme/target/nvmet.h @@ -611,4 +611,10 @@ static inline sector_t nvmet_lba_to_sect(struct nvmet_ns *ns, __le64 lba) return le64_to_cpu(lba) << (ns->blksize_shift - SECTOR_SHIFT); }
+static inline bool nvmet_use_inline_bvec(struct nvmet_req *req) +{ + return req->transfer_len <= NVMET_MAX_INLINE_DATA_LEN && + req->sg_cnt <= NVMET_MAX_INLINE_BIOVEC; +} + #endif /* _NVMET_H */