[SCSI] bsg: update sg_io_v4 structure

This updates sg_io_v4 structure (based on Doug's RFC, release 1.3).

The major changes are:

- add dout_resid field
- increase tag size to 64 bits to comply with SAM-4 and SRP
- add dout_iovec_count and din_iovec_count

dout_iovec_count and din_iovec_count aren't supported now. I'm not
sure whether they will be supported or not but they were added for the
possible future changes.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/block/bsg.c b/block/bsg.c
index d60eee5..ed26468 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -1,5 +1,5 @@
 /*
- * bsg.c - block layer implementation of the sg v3 interface
+ * bsg.c - block layer implementation of the sg v4 interface
  *
  * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs
  * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com>
@@ -421,7 +421,6 @@
 	hdr->info = 0;
 	if (hdr->device_status || hdr->transport_status || hdr->driver_status)
 		hdr->info |= SG_INFO_CHECK;
-	hdr->din_resid = rq->data_len;
 	hdr->response_len = 0;
 
 	if (rq->sense_len && hdr->response) {
@@ -437,9 +436,14 @@
 	}
 
 	if (rq->next_rq) {
+		hdr->dout_resid = rq->data_len;
+		hdr->din_resid = rq->next_rq->data_len;
 		blk_rq_unmap_user(bidi_bio);
 		blk_put_request(rq->next_rq);
-	}
+	} else if (rq_data_dir(rq) == READ)
+		hdr->din_resid = rq->data_len;
+	else
+		hdr->dout_resid = rq->data_len;
 
 	blk_rq_unmap_user(bio);
 	blk_put_request(rq);