2 files changed, 21 insertions, 24 deletions

diff --git a/block/elevator.c b/block/elevator.c
index 96a61e029ce5..2fc269f69726 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -323,7 +323,8 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where,
                 /*
                  * toggle ordered color
                  */
-                q->ordcolor ^= 1;
+                if (blk_barrier_rq(rq))
+                        q->ordcolor ^= 1;
 
                 /*
                  * barriers implicitly indicate back insertion
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index d38b4afa37ef..ee5ed98db4cd 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -508,7 +508,7 @@ static inline struct request *start_ordered(request_queue_t *q,
 
 int blk_do_ordered(request_queue_t *q, struct request **rqp)
 {
-        struct request *rq = *rqp, *allowed_rq;
+        struct request *rq = *rqp;
         int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
 
         if (!q->ordseq) {
@@ -532,32 +532,26 @@ int blk_do_ordered(request_queue_t *q, struct request **rqp)
                 }
         }
 
+        /*
+         * Ordered sequence in progress
+         */
+
+        /* Special requests are not subject to ordering rules. */
+        if (!blk_fs_request(rq) &&
+            rq != &q->pre_flush_rq && rq != &q->post_flush_rq)
+                return 1;
+
         if (q->ordered & QUEUE_ORDERED_TAG) {
+                /* Ordered by tag.  Blocking the next barrier is enough. */
                 if (is_barrier && rq != &q->bar_rq)
                         *rqp = NULL;
-                return 1;
-        }
-
-        switch (blk_ordered_cur_seq(q)) {
-        case QUEUE_ORDSEQ_PREFLUSH:
-                allowed_rq = &q->pre_flush_rq;
-                break;
-        case QUEUE_ORDSEQ_BAR:
-                allowed_rq = &q->bar_rq;
-                break;
-        case QUEUE_ORDSEQ_POSTFLUSH:
-                allowed_rq = &q->post_flush_rq;
-                break;
-        default:
-                allowed_rq = NULL;
-                break;
+        } else {
+                /* Ordered by draining.  Wait for turn. */
+                WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q));
+                if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q))
+                        *rqp = NULL;
         }
 
-        if (rq != allowed_rq &&
-            (blk_fs_request(rq) || rq == &q->pre_flush_rq ||
-             rq == &q->post_flush_rq))
-                *rqp = NULL;
-
         return 1;
 }
 
@@ -2579,6 +2573,8 @@ void disk_round_stats(struct gendisk *disk)
         disk->stamp = now;
 }
 
+EXPORT_SYMBOL_GPL(disk_round_stats);
+
 /*
  * queue lock must be held
  */
@@ -3451,7 +3447,7 @@ int __init blk_dev_init(void)
         iocontext_cachep = kmem_cache_create("blkdev_ioc",
                         sizeof(struct io_context), 0, SLAB_PANIC, NULL, NULL);
 
-        for (i = 0; i < NR_CPUS; i++)
+        for_each_cpu(i)
                 INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
 
         open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);