From: Logan Gunthorpe <logang@deltatee.com>
Date: Fri, 16 Oct 2020 16:19:05 -0600
Subject: [PATCH] nvmet: cleanup nvmet_passthru_map_sg()
Git-commit: 5e063101ffacf7c14797f5185c58a967ca83c79f
Patch-mainline: v5.10-rc1
References: jsc#SLE-15608
Clean up some confusing elements of nvmet_passthru_map_sg() by returning
early if the request is greater than the maximum bio size. This allows
us to drop the sg_cnt variable.
This should not result in any functional change but makes the code
clearer and more understandable. The original code allocated a truncated
bio then would return EINVAL when bio_add_pc_page() filled that bio. The
new code just returns EINVAL early if this would happen.
Fixes: c1fef73f793b ("nvmet: add passthru code to process commands")
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Suggested-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/nvme/target/passthru.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
index 323046e1d67f..0814cba8298a 100644
--- a/drivers/nvme/target/passthru.c
+++ b/drivers/nvme/target/passthru.c
@@ -187,18 +187,20 @@ static void nvmet_passthru_req_done(struct request *rq,
static int nvmet_passthru_map_sg(struct nvmet_req *req, struct request *rq)
{
- int sg_cnt = req->sg_cnt;
struct scatterlist *sg;
int op_flags = 0;
struct bio *bio;
int i, ret;
+ if (req->sg_cnt > BIO_MAX_PAGES)
+ return -EINVAL;
+
if (req->cmd->common.opcode == nvme_cmd_flush)
op_flags = REQ_FUA;
else if (nvme_is_write(req->cmd))
op_flags = REQ_SYNC | REQ_IDLE;
- bio = bio_alloc(GFP_KERNEL, min(sg_cnt, BIO_MAX_PAGES));
+ bio = bio_alloc(GFP_KERNEL, req->sg_cnt);
bio->bi_end_io = bio_put;
bio->bi_opf = req_op(rq) | op_flags;
@@ -208,7 +210,6 @@ static int nvmet_passthru_map_sg(struct nvmet_req *req, struct request *rq)
bio_put(bio);
return -EINVAL;
}
- sg_cnt--;
}
ret = blk_rq_append_bio(rq, &bio);
--
2.16.4