block: restore the meaning of rq->data_len to the true data length

The meaning of rq->data_len was changed to the length of an allocated
buffer from the true data length. It breaks SG_IO friends and
bsg. This patch restores the meaning of rq->data_len to the true data
length and adds rq->extra_len to store an extended length (due to
drain buffer and padding).

This patch also removes the code to update bio in blk_rq_map_user
introduced by the commit 40b01b9bbdf51ae543a04744283bf2d56c4a6afa.
The commit adjusts bio according to memory alignment
(queue_dma_alignment). However, memory alignment is NOT padding
alignment. This adjustment also breaks SG_IO friends and bsg. Padding
alignment needs to be fixed in a proper way (by a separate patch).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>

7 files changed, 13 insertions, 18 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 2d7e3a2f56c4..a248cf1c98dd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -127,7 +127,6 @@ void rq_init(struct request_queue *q, struct request *rq)
         rq->nr_hw_segments = 0;
         rq->ioprio = 0;
         rq->special = NULL;
-        rq->raw_data_len = 0;
         rq->buffer = NULL;
         rq->tag = -1;
         rq->errors = 0;
@@ -135,6 +134,7 @@ void rq_init(struct request_queue *q, struct request *rq)
         rq->cmd_len = 0;
         memset(rq->cmd, 0, sizeof(rq->cmd));
         rq->data_len = 0;
+        rq->extra_len = 0;
         rq->sense_len = 0;
         rq->data = NULL;
         rq->sense = NULL;
@@ -2018,7 +2018,6 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
         rq->hard_cur_sectors = rq->current_nr_sectors;
         rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio);
         rq->buffer = bio_data(bio);
-        rq->raw_data_len = bio->bi_size;
         rq->data_len = bio->bi_size;
 
         rq->bio = rq->biotail = bio;
diff --git a/block/blk-map.c b/block/blk-map.c
index 09f7fd0bcb73..f5598322954d 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -19,7 +19,6 @@ int blk_rq_append_bio(struct request_queue *q, struct request *rq,
                 rq->biotail->bi_next = bio;
                 rq->biotail = bio;
 
-                rq->raw_data_len += bio->bi_size;
                 rq->data_len += bio->bi_size;
         }
         return 0;
@@ -151,11 +150,8 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
          */
         if (len & queue_dma_alignment(q)) {
                 unsigned int pad_len = (queue_dma_alignment(q) & ~len) + 1;
-                struct bio *bio = rq->biotail;
 
-                bio->bi_io_vec[bio->bi_vcnt - 1].bv_len += pad_len;
-                bio->bi_size += pad_len;
-                rq->data_len += pad_len;
+                rq->extra_len += pad_len;
         }
 
         rq->buffer = rq->data = NULL;
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 7506c4fe0264..0f58616bcd7f 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -231,7 +231,7 @@ new_segment:
                             ((unsigned long)q->dma_drain_buffer) &
                             (PAGE_SIZE - 1));
                 nsegs++;
-                rq->data_len += q->dma_drain_size;
+                rq->extra_len += q->dma_drain_size;
         }
 
         if (sg)
diff --git a/block/bsg.c b/block/bsg.c
index 7f3c09549e4b..8917c5174dc2 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -437,14 +437,14 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
         }
 
         if (rq->next_rq) {
-                hdr->dout_resid = rq->raw_data_len;
-                hdr->din_resid = rq->next_rq->raw_data_len;
+                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->raw_data_len;
+                hdr->din_resid = rq->data_len;
         else
-                hdr->dout_resid = rq->raw_data_len;
+                hdr->dout_resid = rq->data_len;
 
         /*
          * If the request generated a negative error number, return it
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index e993cac4911d..a2c3a936ebf9 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -266,7 +266,7 @@ static int blk_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr,
         hdr->info = 0;
         if (hdr->masked_status || hdr->host_status || hdr->driver_status)
                 hdr->info |= SG_INFO_CHECK;
-        hdr->resid = rq->raw_data_len;
+        hdr->resid = rq->data_len;
         hdr->sb_len_wr = 0;
 
         if (rq->sense_len && hdr->sbp) {
@@ -528,8 +528,8 @@ 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->raw_data_len = 0;
         rq->data_len = 0;
+        rq->extra_len = 0;
         rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
         memset(rq->cmd, 0, sizeof(rq->cmd));
         rq->cmd[0] = cmd;
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 7b1f1ee8131d..fe47922dd69e 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2538,7 +2538,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
         }
 
         qc->tf.command = ATA_CMD_PACKET;
-        qc->nbytes = scsi_bufflen(scmd);
+        qc->nbytes = scsi_bufflen(scmd) + scmd->request->extra_len;
 
         /* check whether ATAPI DMA is safe */
         if (!using_pio && ata_check_atapi_dma(qc))
@@ -2549,7 +2549,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
          * want to set it properly, and for DMA where it is
          * effectively meaningless.
          */
-        nbytes = min(scmd->request->raw_data_len, (unsigned int)63 * 1024);
+        nbytes = min(scmd->request->data_len, (unsigned int)63 * 1024);
 
         /* Most ATAPI devices which honor transfer chunk size don't
          * behave according to the spec when odd chunk size which
@@ -2875,7 +2875,7 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
          * TODO: find out if we need to do more here to
          *       cover scatter/gather case.
          */
-        qc->nbytes = scsi_bufflen(scmd);
+        qc->nbytes = scsi_bufflen(scmd) + scmd->request->extra_len;
 
         /* request result TF and be quiet about device error */
         qc->flags |= ATA_QCFLAG_RESULT_TF | ATA_QCFLAG_QUIET;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6fe67d1939c2..b72526c13ca0 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -216,8 +216,8 @@ struct request {
         unsigned int cmd_len;
         unsigned char cmd[BLK_MAX_CDB];
 
-        unsigned int raw_data_len;
         unsigned int data_len;
+        unsigned int extra_len; /* length of alignment and padding */
         unsigned int sense_len;
         void *data;
         void *sense;