tree 5e36431986907b9fa728a6fbeb819a2738a64c82
parent c1768268f9424410761da57ea71107acae7b03cc
author Tejun Heo <tj@kernel.org> 1330982118 -0800
committer Jens Axboe <axboe@kernel.dk> 1331065643 +0100

blkcg: move per-queue blkg list heads and counters to queue and blkg

Currently, specific policy implementations are responsible for
maintaining list and number of blkgs.  This duplicates code
unnecessarily, and hinders factoring common code and providing blkcg
API with better defined semantics.

After this patch, request_queue hosts list heads and counters and blkg
has list nodes for both policies.  This patch only relocates the
necessary fields and the next patch will actually move management code
into blkcg core.

Note that request_queue->blkg_list[] and ->nr_blkgs[] are hardcoded to
have 2 elements.  This is to avoid include dependency and will be
removed by the next patch.

This patch doesn't introduce any behavior change.

-v2: Now unnecessary conditional on CONFIG_BLK_CGROUP_MODULE removed
     as pointed out by Vivek.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>