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authorLinus Torvalds <torvalds@woody.osdl.org>2006-12-21 00:03:38 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-21 00:03:38 -0800
commit4604096768d3be37ee1a05aee424aceed3e1b56f (patch)
tree56010e180bb32be7e57971e4bb617c28d0d09099 /Documentation
parent8df8bb4adf7e4abb48d29dc16c29eda40a64afed (diff)
parent126ec9a676f601818dc3a85af0552b146410d888 (diff)
downloadlinux-4604096768d3be37ee1a05aee424aceed3e1b56f.tar.bz2
Merge branch 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block
* 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block: [PATCH] block: document io scheduler allow_merge_fn hook [PATCH] cfq-iosched: don't allow sync merges across queues [PATCH] Fixup blk_rq_unmap_user() API [PATCH] __blk_rq_unmap_user() fails to return error [PATCH] __blk_rq_map_user() doesn't need to grab the queue_lock [PATCH] Remove queue merging hooks [PATCH] ->nr_sectors and ->hard_nr_sectors are not used for BLOCK_PC requests [PATCH] cciss: fix XFER_READ/XFER_WRITE in do_cciss_request [PATCH] cciss: set default raid level when reading geometry fails
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/block/biodoc.txt7
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index c6c9a9c10d7f..3adaace328a6 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -946,6 +946,13 @@ elevator_merged_fn called when a request in the scheduler has been
scheduler for example, to reposition the request
if its sorting order has changed.
+elevator_allow_merge_fn called whenever the block layer determines
+ that a bio can be merged into an existing
+ 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.
+
elevator_dispatch_fn fills the dispatch queue with ready requests.
I/O schedulers are free to postpone requests by
not filling the dispatch queue unless @force