From: Tejun Heo <tj@kernel.org>
Date: Wed, 24 Sep 2014 17:31:50 +0000 (-0400)
Subject: percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky
X-Git-Tag: fixes-against-v3.18-rc2~134^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1cae13e75b7a7848c03138636d4eb8d8a5054dd5;p=pandora-kernel.git

percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky

Currently, a percpu_ref which is initialized with
PERPCU_REF_INIT_ATOMIC or switched to atomic mode via
switch_to_atomic() automatically reverts to percpu mode on the first
percpu_ref_reinit().  This makes the atomic mode difficult to use for
cases where a percpu_ref is used as a persistent on/off switch which
may be cycled multiple times.

This patch makes such atomic state sticky so that it survives through
kill/reinit cycles.  After this patch, atomic state is cleared only by
an explicit percpu_ref_switch_to_percpu() call.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
---

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