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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Anna-Maria Gleixner <anna-maria@linutronix.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	bigeasy@linutronix.de, Zhen Lei <thunder.leizhen@huawei.com>,
	Joe Korty <joe.korty@concurrent-rt.com>
Subject: [PATCH 4.4 11/11] rcu: Update documentation of rcu_read_unlock()
Date: Sun,  8 Aug 2021 09:22:46 +0200	[thread overview]
Message-ID: <20210808072217.704630357@linuxfoundation.org> (raw)
In-Reply-To: <20210808072217.322468704@linuxfoundation.org>

From: Anna-Maria Gleixner <anna-maria@linutronix.de>

[ Upstream commit ec84b27f9b3b569f9235413d1945a2006b97b0aa ]

Since commit b4abf91047cf ("rtmutex: Make wait_lock irq safe") the
explanation in rcu_read_unlock() documentation about irq unsafe rtmutex
wait_lock is no longer valid.

Remove it to prevent kernel developers reading the documentation to rely on
it.

Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: bigeasy@linutronix.de
Link: https://lkml.kernel.org/r/20180525090507.22248-2-anna-maria@linutronix.de
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Joe Korty <joe.korty@concurrent-rt.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/rcupdate.h |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -880,9 +880,7 @@ static __always_inline void rcu_read_loc
  * Unfortunately, this function acquires the scheduler's runqueue and
  * priority-inheritance spinlocks.  This means that deadlock could result
  * if the caller of rcu_read_unlock() already holds one of these locks or
- * any lock that is ever acquired while holding them; or any lock which
- * can be taken from interrupt context because rcu_boost()->rt_mutex_lock()
- * does not disable irqs while taking ->wait_lock.
+ * any lock that is ever acquired while holding them.
  *
  * That said, RCU readers are never priority boosted unless they were
  * preempted.  Therefore, one way to avoid deadlock is to make sure



  parent reply	other threads:[~2021-08-08  7:23 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-08  7:22 [PATCH 4.4 00/11] 4.4.280-rc1 review Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 01/11] futex: Rename free_pi_state() to put_pi_state() Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 02/11] futex: Cleanup refcounting Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 03/11] futex,rt_mutex: Introduce rt_mutex_init_waiter() Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 04/11] futex: Pull rt_mutex_futex_unlock() out from under hb->lock Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 05/11] futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock() Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 06/11] futex: Futex_unlock_pi() determinism Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 07/11] rtmutex: Make wait_lock irq safe Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 08/11] futex: Handle transient "ownerless" rtmutex state correctly Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 09/11] futex: Avoid freeing an active timer Greg Kroah-Hartman
2021-08-08  7:22 ` [PATCH 4.4 10/11] futex,rt_mutex: Fix rt_mutex_cleanup_proxy_lock() Greg Kroah-Hartman
2021-08-08  7:22 ` Greg Kroah-Hartman [this message]
2021-08-08 16:00 ` [PATCH 4.4 00/11] 4.4.280-rc1 review Guenter Roeck
2021-08-10 15:44   ` Greg Kroah-Hartman
2021-08-09 14:14 ` Naresh Kamboju
  -- strict thread matches above, loose matches on Subject: below --
2021-08-02 13:46 [PATCH 4.4 00/11] Fix a potential infinite loop in RT futex-pi scenarios Zhen Lei
2021-08-02 13:46 ` [PATCH 4.4 11/11] rcu: Update documentation of rcu_read_unlock() Zhen Lei

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