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-rw-r--r--Documentation/block/biodoc.txt6
1 files changed, 5 insertions, 1 deletions
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index 6b972b287795..5aabc08de811 100644
--- 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