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, 1 insertions, 5 deletions

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;