Commit 02db9954 authored by Ming Lei's avatar Ming Lei Committed by Christoph Hellwig
Browse files

nvmet: fix building bvec from sg list 



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: default avatarYi Zhang <yi.zhang@redhat.com>
Fixes: 3a85a5de ("nvme-loop: add a NVMe loopback host driver")

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent cc2278c4

drivers/nvme/target/io-cmd-file.c

+10 −10
Original line number Diff line number Diff line
@@ -75,11 +75,11 @@ err: 
	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);

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