[SCSI] bsg: add large command support

This enables bsg to handle the request length larger than BLK_MAX_CDB
(mainly for the variable length CDB format).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/block/bsg.c b/block/bsg.c
index 23ea4fd1a66..d8b889d2e41 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -174,7 +174,11 @@ unlock:
 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
                                 struct sg_io_v4 *hdr, int has_write_perm)
 {
-        memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
+        if (hdr->request_len > BLK_MAX_CDB) {
+                rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
+                if (!rq->cmd)
+                        return -ENOMEM;
+        }
 
         if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request,
                            hdr->request_len))
@@ -211,8 +215,6 @@ bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
 
         if (hdr->guard != 'Q')
                 return -EINVAL;
-        if (hdr->request_len > BLK_MAX_CDB)
-                return -EINVAL;
         if (hdr->dout_xfer_len > (q->max_sectors << 9) ||
             hdr->din_xfer_len > (q->max_sectors << 9))
                 return -EIO;
@@ -302,6 +304,8 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
         }
         return rq;
 out:
+        if (rq->cmd != rq->__cmd)
+                kfree(rq->cmd);
         blk_put_request(rq);
         if (next_rq) {
                 blk_rq_unmap_user(next_rq->bio);
@@ -455,6 +459,8 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
                 ret = rq->errors;
 
         blk_rq_unmap_user(bio);
+        if (rq->cmd != rq->__cmd)
+                kfree(rq->cmd);
         blk_put_request(rq);
 
         return ret;