bsg: add sg_io_v4 structure

This patch adds sg_io_v4 structure that Doug proposed last month.

There's one major change from the RFC. I dropped iovec, which needs
compat stuff. The bsg code simply calls blk_rq_map_user against
dout_xferp/din_xferp. So if possible, the page frames are directly
mapped. If not possible, the block layer allocates new page frames and
does memory copies.

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

1 files changed, 43 insertions, 0 deletions

diff --git a/include/linux/bsg.h b/include/linux/bsg.h
index dc0d7282c4cb..0d212cc06abf 100644
--- a/include/linux/bsg.h
+++ b/include/linux/bsg.h
@@ -1,6 +1,47 @@
 #ifndef BSG_H
 #define BSG_H
 
+struct sg_io_v4 {
+        int32_t guard;          /* [i] 'Q' to differentiate from v3 */
+        uint32_t protocol;      /* [i] 0 -> SCSI , .... */
+        uint32_t subprotocol;   /* [i] 0 -> SCSI command, 1 -> SCSI task
+                                   management function, .... */
+
+        uint32_t request_len;   /* [i] in bytes */
+        uint64_t request;       /* [i], [*i] {SCSI: cdb} */
+        uint32_t request_attr;  /* [i] {SCSI: task attribute} */
+        uint32_t request_tag;   /* [i] {SCSI: task tag (only if flagged)} */
+        uint32_t request_priority;      /* [i] {SCSI: task priority} */
+        uint32_t max_response_len;      /* [i] in bytes */
+        uint64_t response;      /* [i], [*o] {SCSI: (auto)sense data} */
+
+        /* "din_" for data in (from device); "dout_" for data out (to device) */
+        uint32_t dout_xfer_len; /* [i] bytes to be transferred to device */
+        uint32_t din_xfer_len;  /* [i] bytes to be transferred from device */
+        uint64_t dout_xferp;    /* [i], [*i] */
+        uint64_t din_xferp;     /* [i], [*o] */
+
+        uint32_t timeout;       /* [i] units: millisecond */
+        uint32_t flags;         /* [i] bit mask */
+        uint64_t usr_ptr;       /* [i->o] unused internally */
+        uint32_t spare_in;      /* [i] */
+
+        uint32_t driver_status; /* [o] 0 -> ok */
+        uint32_t transport_status;      /* [o] 0 -> ok */
+        uint32_t device_status; /* [o] {SCSI: command completion status} */
+        uint32_t retry_delay;   /* [o] {SCSI: status auxiliary information} */
+        uint32_t info;          /* [o] additional information */
+        uint32_t duration;      /* [o] time to complete, in milliseconds */
+        uint32_t response_len;  /* [o] bytes of response actually written */
+        int32_t din_resid;      /* [o] actual_din_xfer_len - din_xfer_len */
+        uint32_t generated_tag; /* [o] {SCSI: task tag that transport chose} */
+        uint32_t spare_out;     /* [o] */
+
+        uint32_t padding;
+};
+
+#ifdef __KERNEL__
+
 #if defined(CONFIG_BLK_DEV_BSG)
 struct bsg_class_device {
         struct class_device *class_dev;
@@ -18,4 +59,6 @@ struct bsg_class_device { };
 #define bsg_unregister_disk(disk)       do { } while (0)
 #endif
 
+#endif /* __KERNEL__ */
+
 #endif