bsg: add SCSI transport-level request support

This enables bsg to handle SCSI transport-level request like SAS
management protocol (SMP).

- add BSG_SUB_PROTOCOL_{SCSI_CMD, SCSI_TMF, SCSI_TRANSPORT} definitions.
- SCSI transport-level requests skip blk_verify_command().

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

2 files changed, 27 insertions, 6 deletions

diff --git a/block/bsg.c b/block/bsg.c
index 13ecc951a4c0..461c9f56f3ee 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -208,7 +208,11 @@ static int blk_fill_sgv4_hdr_rq(request_queue_t *q, struct request *rq,
         if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request,
                            hdr->request_len))
                 return -EFAULT;
-        if (blk_verify_command(rq->cmd, has_write_perm))
+
+        if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
+                if (blk_verify_command(rq->cmd, has_write_perm))
+                        return -EPERM;
+        } else if (!capable(CAP_SYS_RAWIO))
                 return -EPERM;
 
         /*
@@ -232,6 +236,8 @@ static int blk_fill_sgv4_hdr_rq(request_queue_t *q, struct request *rq,
 static int
 bsg_validate_sgv4_hdr(request_queue_t *q, struct sg_io_v4 *hdr, int *rw)
 {
+        int ret = 0;
+
         if (hdr->guard != 'Q')
                 return -EINVAL;
         if (hdr->request_len > BLK_MAX_CDB)
@@ -240,13 +246,22 @@ bsg_validate_sgv4_hdr(request_queue_t *q, struct sg_io_v4 *hdr, int *rw)
             hdr->din_xfer_len > (q->max_sectors << 9))
                 return -EIO;
 
-        /* not supported currently */
-        if (hdr->protocol || hdr->subprotocol)
-                return -EINVAL;
+        switch (hdr->protocol) {
+        case BSG_PROTOCOL_SCSI:
+                switch (hdr->subprotocol) {
+                case BSG_SUB_PROTOCOL_SCSI_CMD:
+                case BSG_SUB_PROTOCOL_SCSI_TRANSPORT:
+                        break;
+                default:
+                        ret = -EINVAL;
+                }
+                break;
+        default:
+                ret = -EINVAL;
+        }
 
         *rw = hdr->dout_xfer_len ? WRITE : READ;
-
-        return 0;
+        return ret;
 }
 
 /*
diff --git a/include/linux/bsg.h b/include/linux/bsg.h
index 0dd01f90ba5e..bd998ca6cb2e 100644
--- a/include/linux/bsg.h
+++ b/include/linux/bsg.h
@@ -1,6 +1,12 @@
 #ifndef BSG_H
 #define BSG_H
 
+#define BSG_PROTOCOL_SCSI               0
+
+#define BSG_SUB_PROTOCOL_SCSI_CMD       0
+#define BSG_SUB_PROTOCOL_SCSI_TMF       1
+#define BSG_SUB_PROTOCOL_SCSI_TRANSPORT 2
+
 struct sg_io_v4 {
         __s32 guard;            /* [i] 'Q' to differentiate from v3 */
         __u32 protocol;         /* [i] 0 -> SCSI , .... */