block: remove struct request buffer member

This was used in the olden days, back when onions were proper
yellow. Basically it mapped to the current buffer to be
transferred. With highmem being added more than a decade ago,
most drivers map pages out of a bio, and rq->buffer isn't
pointing at anything valid.

Convert old style drivers to just use bio_data().

For the discard payload use case, just reference the page
in the bio.

Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 0 insertions, 3 deletions

diff --git a/block/blk-map.c b/block/blk-map.c
index f7b22bc21518..f890d4345b0c 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -155,7 +155,6 @@ 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 = NULL;
         return 0;
 unmap_rq:
         blk_rq_unmap_user(bio);
@@ -238,7 +237,6 @@ 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 = NULL;
         return 0;
 }
 EXPORT_SYMBOL(blk_rq_map_user_iov);
@@ -325,7 +323,6 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
         }
 
         blk_queue_bounce(q, &rq->bio);
-        rq->buffer = NULL;
         return 0;
 }
 EXPORT_SYMBOL(blk_rq_map_kern);