tree 93d3217dc15a8183c8e6b29b36862caef01546d7
parent 26a2ac009c2b07e1959c8864ca23486c1c485587
author Jens Axboe <jens.axboe@oracle.com> 1240481696 +0200
committer Jens Axboe <jens.axboe@oracle.com> 1240556062 +0200

cfq-iosched: fix bug with aliased request and cooperation detection

cfq_prio_tree_lookup() should return the direct match, yet it always
returns zero. Fix that.

cfq_prio_tree_add() assumes that we don't get a direct match, while
it is very possible that we do. Using O_DIRECT, you can have different
cfqq with matching requests, since you don't have the page cache
to serialize things for you. Fix this bug by only adding the cfqq if
there isn't an existing match.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>