tree f0b9074069777c430045e7be803d8c5a2187ecc9
parent c2fda5fed81eea077363b285b66eafce20dfd45a
author Jens Axboe <jens.axboe@oracle.com> 1166776733 +0100
committer Linus Torvalds <torvalds@woody.osdl.org> 1166825588 -0800

[PATCH] cfq-iosched: tighten allow merge criteria

The logic in cfq_allow_merge() wasn't clear enough - basically allow
merging for the same queues only.  Do a fast check for 'rq and bio both
sync/async' before doing the cfqq hash lookup.

This is verified to work with the fixed elv_try_merge() from commit
bb4067e34159648d394943d5e2a011f838bff22f.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>