scsi: bsg-lib: Fix commands without data transfer in bsg_transport_sg_io_fn()

Set ret to 0 after the initial permission checks to avoid leaking -EPERM
for commands without data transfer.

Link: https://lore.kernel.org/r/20210731074027.1185545-3-hch@lst.de
Fixes: 75ca56409e5b ("scsi: bsg: Move the whole request execution into the SCSI/transport handlers")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/block/bsg-lib.c b/block/bsg-lib.c
index 239ebf7..ccb9827 100644 (file)
--- a/block/bsg-lib.c
+++ b/block/bsg-lib.c
@@ -72,6 +72,7 @@ static int bsg_transport_sg_io_fn(struct request_queue *q, struct sg_io_v4 *hdr,
                job->bidi_bio = NULL;
        }
 
+       ret = 0;
        if (hdr->dout_xfer_len) {
                ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->dout_xferp),
                                hdr->dout_xfer_len, GFP_KERNEL);