Merge branch 'for-3.19/core' of git://git.kernel.dk/linux-block

[karo-tx-linux.git] / Documentation / block / biodoc.txt

diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index 6b972b287795b73d84fa7a390d34aaec821163e1..5aabc08de811d49ba898d550a0c2ff98ab3964a5 100644 (file)
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -942,7 +942,11 @@ elevator_allow_merge_fn            called whenever the block layer determines
                                request safely. The io scheduler may still
                                want to stop a merge at this point if it
                                results in some sort of conflict internally,
-                               this hook allows it to do that.
+                               this hook allows it to do that. Note however
+                               that two *requests* can still be merged at later
+                               time. Currently the io scheduler has no way to
+                               prevent that. It can only learn about the fact
+                               from elevator_merge_req_fn callback.
 
 elevator_dispatch_fn*          fills the dispatch queue with ready requests.
                                I/O schedulers are free to postpone requests by