There are two mistakes for building bvec from sg list for file backed ns:

- use request data length to compute number of io vector, this way doesn't consider sg->offset, and the result may be smaller than required io vectors

- bvec->bv_len isn't capped by sg->length

This patch fixes this issue by building bvec from sg directly, given the whole IO stack is ready for multi-page bvec.

Reported-by: Yi Zhang yi.zhang@redhat.com Fixes: 3a85a5de29ea ("nvme-loop: add a NVMe loopback host driver") Cc: Yi Zhang yi.zhang@redhat.com Cc: Sagi Grimberg sagi@grimberg.me Cc: Chaitanya Kulkarni chaitanya.kulkarni@wdc.com

(Backporting depends on the stable-only patch of 'nvmet: set loop queue's segment boundary mask as PAGE_SIZE - 1') Cc: stable@vger.kernel.org Signed-off-by: Ming Lei ming.lei@redhat.com --- drivers/nvme/target/io-cmd-file.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/nvme/target/io-cmd-file.c b/drivers/nvme/target/io-cmd-file.c index 3e43212d3c1c..bc6ebb51b0bf 100644 --- a/drivers/nvme/target/io-cmd-file.c +++ b/drivers/nvme/target/io-cmd-file.c @@ -75,11 +75,11 @@ int nvmet_file_ns_enable(struct nvmet_ns *ns) return ret; }

-static void nvmet_file_init_bvec(struct bio_vec *bv, struct sg_page_iter *iter) +static void nvmet_file_init_bvec(struct bio_vec *bv, struct scatterlist *sg) { - bv->bv_page = sg_page_iter_page(iter); - bv->bv_offset = iter->sg->offset; - bv->bv_len = PAGE_SIZE - iter->sg->offset; + bv->bv_page = sg_page(sg); + bv->bv_offset = sg->offset; + bv->bv_len = sg->length; }

static ssize_t nvmet_file_submit_bvec(struct nvmet_req *req, loff_t pos, @@ -128,14 +128,14 @@ static void nvmet_file_io_done(struct kiocb *iocb, long ret, long ret2)

static bool nvmet_file_execute_io(struct nvmet_req *req, int ki_flags) { - ssize_t nr_bvec = DIV_ROUND_UP(req->data_len, PAGE_SIZE); - struct sg_page_iter sg_pg_iter; + ssize_t nr_bvec = req->sg_cnt; unsigned long bv_cnt = 0; bool is_sync = false; size_t len = 0, total_len = 0; ssize_t ret = 0; loff_t pos; - + int i; + struct scatterlist *sg;

if (req->f.mpool_alloc && nr_bvec > NVMET_MAX_MPOOL_BVEC) is_sync = true; @@ -147,8 +147,8 @@ static bool nvmet_file_execute_io(struct nvmet_req *req, int ki_flags) }

memset(&req->f.iocb, 0, sizeof(struct kiocb)); - for_each_sg_page(req->sg, &sg_pg_iter, req->sg_cnt, 0) { - nvmet_file_init_bvec(&req->f.bvec[bv_cnt], &sg_pg_iter); + for_each_sg(req->sg, sg, req->sg_cnt, i) { + nvmet_file_init_bvec(&req->f.bvec[bv_cnt], sg); len += req->f.bvec[bv_cnt].bv_len; total_len += req->f.bvec[bv_cnt].bv_len; bv_cnt++; @@ -225,7 +225,7 @@ static void nvmet_file_submit_buffered_io(struct nvmet_req *req)

static void nvmet_file_execute_rw(struct nvmet_req *req) { - ssize_t nr_bvec = DIV_ROUND_UP(req->data_len, PAGE_SIZE); + ssize_t nr_bvec = req->sg_cnt;

if (!req->sg_cnt || !nr_bvec) { nvmet_req_complete(req, 0);