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>

1 files changed, 3 insertions, 3 deletions

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;