[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>

block/bsg.c

 /*
- * 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 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
 	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 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
 	}
 
 	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);

include/linux/bsg.h

@@ -15,14 +15,18 @@ struct sg_io_v4 {
 
 	__u32 request_len;	/* [i] in bytes */
 	__u64 request;		/* [i], [*i] {SCSI: cdb} */
+	__u64 request_tag;	/* [i] {SCSI: task tag (only if flagged)} */
 	__u32 request_attr;	/* [i] {SCSI: task attribute} */
-	__u32 request_tag;	/* [i] {SCSI: task tag (only if flagged)} */
 	__u32 request_priority;	/* [i] {SCSI: task priority} */
+	__u32 request_extra;	/* [i] {spare, for padding} */
 	__u32 max_response_len;	/* [i] in bytes */
 	__u64 response;		/* [i], [*o] {SCSI: (auto)sense data} */
 
-	/* "din_" for data in (from device); "dout_" for data out (to device) */
+        /* "dout_": data out (to device); "din_": data in (from device) */
+	__u32 dout_iovec_count;	/* [i] 0 -> "flat" dout transfer else
+				   dout_xfer points to array of iovec */
 	__u32 dout_xfer_len;	/* [i] bytes to be transferred to device */
+	__u32 din_iovec_count;	/* [i] 0 -> "flat" din transfer */
 	__u32 din_xfer_len;	/* [i] bytes to be transferred from device */
 	__u64 dout_xferp;	/* [i], [*i] */
 	__u64 din_xferp;	/* [i], [*o] */
@@ -39,8 +43,9 @@ struct sg_io_v4 {
 	__u32 info;		/* [o] additional information */
 	__u32 duration;		/* [o] time to complete, in milliseconds */
 	__u32 response_len;	/* [o] bytes of response actually written */
-	__s32 din_resid;	/* [o] actual_din_xfer_len - din_xfer_len */
-	__u32 generated_tag;	/* [o] {SCSI: task tag that transport chose} */
+	__s32 din_resid;	/* [o] din_xfer_len - actual_din_xfer_len */
+	__s32 dout_resid;	/* [o] dout_xfer_len - actual_dout_xfer_len */
+	__u64 generated_tag;	/* [o] {SCSI: transport generated task tag} */
 	__u32 spare_out;	/* [o] */
 
 	__u32 padding;