block: share request flush fields with elevator_private

[linux-2.6-block.git] / include / linux / blkdev.h

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6d7e9afd08c3833893271bb5d1dadbdfb776698c..12bb426949e9f68a42c5b505db6c63650d9b6128 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -99,25 +99,26 @@ struct request {
        /*
         * The rb_node is only used inside the io scheduler, requests
         * are pruned when moved to the dispatch queue. So let the
-        * flush fields share space with the rb_node.
+        * completion_data share space with the rb_node.
         */
        union {
                struct rb_node rb_node; /* sort/lookup */
-               struct {
-                       unsigned int                    seq;
-                       struct list_head                list;
-               } flush;
+               void *completion_data;
        };
 
-       void *completion_data;
-
        /*
         * Three pointers are available for the IO schedulers, if they need
-        * more they have to dynamically allocate it.
+        * more they have to dynamically allocate it.  Flush requests are
+        * never put on the IO scheduler. So let the flush fields share
+        * space with the three elevator_private pointers.
         */
-       void *elevator_private;
-       void *elevator_private2;
-       void *elevator_private3;
+       union {
+               void *elevator_private[3];
+               struct {
+                       unsigned int            seq;
+                       struct list_head        list;
+               } flush;
+       };
 
        struct gendisk *rq_disk;
        unsigned long start_time;