Merge branch 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block

* 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block: (46 commits)
  xen-blkfront: disable barrier/flush write support
  Added blk-lib.c and blk-barrier.c was renamed to blk-flush.c
  block: remove BLKDEV_IFL_WAIT
  aic7xxx_old: removed unused 'req' variable
  block: remove the BH_Eopnotsupp flag
  block: remove the BLKDEV_IFL_BARRIER flag
  block: remove the WRITE_BARRIER flag
  swap: do not send discards as barriers
  fat: do not send discards as barriers
  ext4: do not send discards as barriers
  jbd2: replace barriers with explicit flush / FUA usage
  jbd2: Modify ASYNC_COMMIT code to not rely on queue draining on barrier
  jbd: replace barriers with explicit flush / FUA usage
  nilfs2: replace barriers with explicit flush / FUA usage
  reiserfs: replace barriers with explicit flush / FUA usage
  gfs2: replace barriers with explicit flush / FUA usage
  btrfs: replace barriers with explicit flush / FUA usage
  xfs: replace barriers with explicit flush / FUA usage
  block: pass gfp_mask and flags to sb_issue_discard
  dm: convey that all flushes are processed as empty
  ...

1 files changed, 7 insertions, 1 deletions

diff --git a/block/blk.h b/block/blk.h
index f864012ec300..1e675e5ade02 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -51,6 +51,8 @@ static inline void blk_clear_rq_complete(struct request *rq)
  */
 #define ELV_ON_HASH(rq)         (!hlist_unhashed(&(rq)->hash))
 
+struct request *blk_do_flush(struct request_queue *q, struct request *rq);
+
 static inline struct request *__elv_next_request(struct request_queue *q)
 {
         struct request *rq;
@@ -58,7 +60,11 @@ static inline struct request *__elv_next_request(struct request_queue *q)
         while (1) {
                 while (!list_empty(&q->queue_head)) {
                         rq = list_entry_rq(q->queue_head.next);
-                        if (blk_do_ordered(q, &rq))
+                        if (!(rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) ||
+                            rq == &q->flush_rq)
+                                return rq;
+                        rq = blk_do_flush(q, rq);
+                        if (rq)
                                 return rq;
                 }