From: Tejun Heo <tj@kernel.org>
Date: Tue, 14 May 2013 20:52:31 +0000 (-0700)
Subject: blkcg: invoke blkcg_policy->pd_init() after parent is linked
X-Git-Tag: v3.11-rc1~21^2~32
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=db61367038dcd222476881cb09fd54661b3cd508;p=pandora-kernel.git

blkcg: invoke blkcg_policy->pd_init() after parent is linked

Currently, when creating a new blkcg_gq, each policy's pd_init_fn() is
invoked in blkg_alloc() before the parent is linked.  This makes it
difficult for policies to perform initializations which are dependent
on the parent.

This patch moves pd_init_fn() invocations to blkg_create() after the
parent blkg is linked where the new blkg is fully initialized.  As
this means that blkg_free() can't assume that pd's are initialized,
pd_exit_fn() invocations are moved to __blkg_release().  This
guarantees that pd_exit_fn() is also invoked with fully initialized
blkgs with valid parent pointers.

This will help implementing hierarchy support in blk-throttle.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
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