63 lines
2.2 KiB
Diff
63 lines
2.2 KiB
Diff
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From 5f5393b7a81628b5d68c61780dd289e266d1895c Mon Sep 17 00:00:00 2001
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Wed, 28 Mar 2018 11:15:19 +0200
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Subject: [PATCH 360/365] posix-timers: move the rcu head out of the union
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On RT the timer can be preempted while running and therefore we wait
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with timer_wait_for_callback() for the timer to complete (instead of
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busy looping). The RCU-readlock is held to ensure that this posix timer
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is not removed while we wait on it.
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If the timer is removed then it invokes call_rcu() with a pointer that
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is shared with the hrtimer because it is part of the same union.
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In order to avoid any possible side effects I am moving the rcu pointer
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out of the union.
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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(cherry picked from commit b8401365af110949f12c7cf1fa86b4c0ea069bbd)
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Signed-off-by: Julia Cartwright <julia@ni.com>
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---
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include/linux/posix-timers.h | 2 +-
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kernel/time/posix-timers.c | 4 ++--
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2 files changed, 3 insertions(+), 3 deletions(-)
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diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
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index e4b8678183f5..7bebe3286c4e 100644
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--- a/include/linux/posix-timers.h
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+++ b/include/linux/posix-timers.h
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@@ -92,8 +92,8 @@ struct k_itimer {
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struct alarm alarmtimer;
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ktime_t interval;
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} alarm;
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- struct rcu_head rcu;
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} it;
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+ struct rcu_head rcu;
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};
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struct k_clock {
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diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
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index 558e420c352c..d6d6c1921878 100644
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--- a/kernel/time/posix-timers.c
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+++ b/kernel/time/posix-timers.c
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@@ -577,7 +577,7 @@ static struct k_itimer * alloc_posix_timer(void)
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static void k_itimer_rcu_free(struct rcu_head *head)
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{
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- struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu);
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+ struct k_itimer *tmr = container_of(head, struct k_itimer, rcu);
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kmem_cache_free(posix_timers_cache, tmr);
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}
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@@ -594,7 +594,7 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
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}
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put_pid(tmr->it_pid);
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sigqueue_free(tmr->sigq);
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- call_rcu(&tmr->it.rcu, k_itimer_rcu_free);
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+ call_rcu(&tmr->rcu, k_itimer_rcu_free);
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}
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static struct k_clock *clockid_to_kclock(const clockid_t id)
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--
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2.28.0
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