tree 6e812a7d199557452117ed5e53c98e20cf33f893
parent 3d70f8c617a436c7146ecb81df2265b4626dfe89
author Shaohua Li <shli@kernel.org> 1352201991 +0100
committer Jens Axboe <axboe@kernel.dk> 1352201991 +0100

block CFQ: avoid moving request to different queue

request is queued in cfqq->fifo list. Looks it's possible we are moving a
request from one cfqq to another in request merge case. In such case, adjusting
the fifo list order doesn't make sense and is impossible if we don't iterate
the whole fifo list.

My test does hit one case the two cfqq are different, but didn't cause kernel
crash, maybe it's because fifo list isn't used frequently. Anyway, from the
code logic, this is buggy.

I thought we can re-enable the recusive merge logic after this is fixed.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>