Fix up comments about matching flags between bio and rq

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index b5776c1fd52a..a496727df7ef 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -624,10 +624,6 @@ blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask)
 
         blk_rq_init(q, rq);
 
-        /*
-         * first three bits are identical in rq->cmd_flags and bio->bi_rw,
-         * see bio.h and blkdev.h
-         */
         rq->cmd_flags = rw | REQ_ALLOCED;
 
         if (priv) {
@@ -2012,7 +2008,8 @@ EXPORT_SYMBOL_GPL(blk_end_request_callback);
 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
                      struct bio *bio)
 {
-        /* first two bits are identical in rq->cmd_flags and bio->bi_rw */
+        /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw, and
+           we want BIO_RW_AHEAD (bit 1) to imply REQ_FAILFAST (bit 1). */
         rq->cmd_flags |= (bio->bi_rw & 3);
 
         rq->nr_phys_segments = bio_phys_segments(q, bio);