block, fs, mm, drivers: use bio set/get op accessors

This patch converts the simple bi_rw use cases in the block,
drivers, mm and fs code to set/get the bio operation using
bio_set_op_attrs/bio_op

These should be simple one or two liner cases, so I just did them
in one patch. The next patches handle the more complicated
cases in a module per patch.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-merge.c b/block/blk-merge.c
index b198070..5a03f96 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -172,9 +172,9 @@
 	struct bio *split, *res;
 	unsigned nsegs;
 
-	if ((*bio)->bi_rw & REQ_DISCARD)
+	if (bio_op(*bio) == REQ_OP_DISCARD)
 		split = blk_bio_discard_split(q, *bio, bs, &nsegs);
-	else if ((*bio)->bi_rw & REQ_WRITE_SAME)
+	else if (bio_op(*bio) == REQ_OP_WRITE_SAME)
 		split = blk_bio_write_same_split(q, *bio, bs, &nsegs);
 	else
 		split = blk_bio_segment_split(q, *bio, q->bio_split, &nsegs);
@@ -213,10 +213,10 @@
 	 * This should probably be returning 0, but blk_add_request_payload()
 	 * (Christoph!!!!)
 	 */
-	if (bio->bi_rw & REQ_DISCARD)
+	if (bio_op(bio) == REQ_OP_DISCARD)
 		return 1;
 
-	if (bio->bi_rw & REQ_WRITE_SAME)
+	if (bio_op(bio) == REQ_OP_WRITE_SAME)
 		return 1;
 
 	fbio = bio;
@@ -385,7 +385,7 @@
 	nsegs = 0;
 	cluster = blk_queue_cluster(q);
 
-	if (bio->bi_rw & REQ_DISCARD) {
+	if (bio_op(bio) == REQ_OP_DISCARD) {
 		/*
 		 * This is a hack - drivers should be neither modifying the
 		 * biovec, nor relying on bi_vcnt - but because of
@@ -400,7 +400,7 @@
 		return 0;
 	}
 
-	if (bio->bi_rw & REQ_WRITE_SAME) {
+	if (bio_op(bio) == REQ_OP_WRITE_SAME) {
 single_segment:
 		*sg = sglist;
 		bvec = bio_iovec(bio);