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/fs/exofs/ore.c b/fs/exofs/ore.c
index 7bd8ac8..8bb7280 100644
--- a/fs/exofs/ore.c
+++ b/fs/exofs/ore.c
@@ -878,7 +878,7 @@
 			} else {
 				bio = master_dev->bio;
 				/* FIXME: bio_set_dir() */
-				bio->bi_rw |= REQ_WRITE;
+				bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 			}
 
 			osd_req_write(or, _ios_obj(ios, cur_comp),