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, 4 insertions, 2 deletions

diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index 27de5046708a..968f9e52effa 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -87,13 +87,15 @@ static void do_z2_request(struct request_queue *q)
 		while (len) {
 			unsigned long addr = start & Z2RAM_CHUNKMASK;
 			unsigned long size = Z2RAM_CHUNKSIZE - addr;
+			void *buffer = bio_data(req->bio);
+
 			if (len < size)
 				size = len;
 			addr += z2ram_map[ start >> Z2RAM_CHUNKSHIFT ];
 			if (rq_data_dir(req) == READ)
-				memcpy(req->buffer, (char *)addr, size);
+				memcpy(buffer, (char *)addr, size);
 			else
-				memcpy((char *)addr, req->buffer, size);
+				memcpy((char *)addr, buffer, size);
 			start += size;
 			len -= size;
 		}