apparmor: only get a label reference if the fast path check fails
The common fast path check can be done under rcu_read_lock() and doesn't need a reference count on the label. Only take a reference count if entering the slow path. Fixes reported hackbench regression - sha1 79e178a5 ("Merge tag 'apparmor-pr-2019-12-03' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor") hackbench -l (256000/#grp) -g #grp 128 groups 19.679 ±0.90% - previous sha1 01d1dff6 ("Merge tag 's390-5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux") hackbench -l (256000/#grp) -g #grp 128 groups 3.1689 ±3.04% Reported-by:Vincent Guittot <vincent.guittot@linaro.org> Tested-by:
Vincent Guittot <vincent.guittot@linaro.org> Tested-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Fixes: bce4e7e9 ("apparmor: reduce rcu_read_lock scope for aa_file_perm mediation") Signed-off-by:
John Johansen <john.johansen@canonical.com>
parent
9c95a278
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