block: kill rq->data

Now that all block request data transfer is done via bio, rq->data
isn't used.  Kill it.

While at it, make the roles of rq->special and buffer clear.

[ Impact: drop now unncessary field from struct request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Boaz Harrosh <bharrosh@panasas.com>

5 files changed, 7 insertions, 11 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 0520cc704585..6dd180cf15d2 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -189,10 +189,9 @@ void blk_dump_rq_flags(struct request *rq, char *msg)
                                                 (unsigned long long)rq->sector,
                                                 rq->nr_sectors,
                                                 rq->current_nr_sectors);
-        printk(KERN_INFO "  bio %p, biotail %p, buffer %p, data %p, len %u\n",
+        printk(KERN_INFO "  bio %p, biotail %p, buffer %p, len %u\n",
                                                 rq->bio, rq->biotail,
-                                                rq->buffer, rq->data,
-                                                rq->data_len);
+                                                rq->buffer, rq->data_len);
 
         if (blk_pc_request(rq)) {
                 printk(KERN_INFO "  cdb: ");
diff --git a/block/blk-map.c b/block/blk-map.c
index f103729b462f..694fefad34e7 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -156,7 +156,7 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
         if (!bio_flagged(bio, BIO_USER_MAPPED))
                 rq->cmd_flags |= REQ_COPY_USER;
 
-        rq->buffer = rq->data = NULL;
+        rq->buffer = NULL;
         return 0;
 unmap_rq:
         blk_rq_unmap_user(bio);
@@ -235,7 +235,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
         blk_queue_bounce(q, &bio);
         bio_get(bio);
         blk_rq_bio_prep(q, rq, bio);
-        rq->buffer = rq->data = NULL;
+        rq->buffer = NULL;
         return 0;
 }
 EXPORT_SYMBOL(blk_rq_map_user_iov);
@@ -313,7 +313,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
 
         blk_rq_bio_prep(q, rq, bio);
         blk_queue_bounce(q, &rq->bio);
-        rq->buffer = rq->data = NULL;
+        rq->buffer = NULL;
         return 0;
 }
 EXPORT_SYMBOL(blk_rq_map_kern);
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 82a0ca2f6729..bb9aa43551b2 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -500,7 +500,6 @@ static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk,
 
         rq = blk_get_request(q, WRITE, __GFP_WAIT);
         rq->cmd_type = REQ_TYPE_BLOCK_PC;
-        rq->data = NULL;
         rq->data_len = 0;
         rq->extra_len = 0;
         rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 756ac7c93de0..aa9fc572e45f 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1088,7 +1088,6 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
                         return ret;
         } else {
                 BUG_ON(req->data_len);
-                BUG_ON(req->data);
 
                 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
                 req->buffer = NULL;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index cfeb3c2feb27..12c545e2737c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -211,8 +211,8 @@ struct request {
 
         unsigned short ioprio;
 
-        void *special;
-        char *buffer;
+        void *special;          /* opaque pointer available for LLD use */
+        char *buffer;           /* kaddr of the current segment if available */
 
         int tag;
         int errors;
@@ -229,7 +229,6 @@ struct request {
         unsigned int data_len;
         unsigned int extra_len; /* length of alignment and padding */
         unsigned int sense_len;
-        void *data;
         void *sense;
 
         unsigned long deadline;