linux-kernel - fs_struct refcounting: spinlock vs atomic

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Message-ID: <7547a9ed-a2e7-e975-a3ba-f41abc16f4bc@metux.net>
Date:   Wed, 14 Feb 2018 22:13:59 +0100
From:   Enrico Weigelt <lkml@...ux.net>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: fs_struct refcounting: spinlock vs atomic

Hi folks,

in fork.c, a spinlock is held for fs_struct refcounting, while other
places - eg. switch_task_namespaces uses atomic_dec_and_test() on
the nsproxy.

What's the exact difference here ? Could the atomic counting also used
for fs_struct ?

--mtx

-- 
Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@...ux.net -- +49-151-27565287