From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Anna-Maria Behnsen <anna-maria@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Stephen Boyd <sboyd@kernel.org>,
Guenter Roeck <linux@roeck-us.net>,
Andrew Morton <akpm@linux-foundation.org>,
Julia Lawall <Julia.Lawall@inria.fr>,
Arnd Bergmann <arnd@arndb.de>,
Viresh Kumar <viresh.kumar@linaro.org>,
Marc Zyngier <maz@kernel.org>,
Marcel Holtmann <marcel@holtmann.org>,
Johan Hedberg <johan.hedberg@gmail.com>,
Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
linux-bluetooth@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
netdev@vger.kernel.org
Subject: [patch V2 08/17] timers: Use del_timer_sync() even on UP
Date: Tue, 22 Nov 2022 18:44:57 +0100 (CET) [thread overview]
Message-ID: <20221122173648.560770928@linutronix.de> (raw)
In-Reply-To: 20221122171312.191765396@linutronix.de
del_timer_sync() is assumed to be pointless on uniprocessor systems and can
be mapped to del_timer() because in theory del_timer() can never be invoked
while the timer callback function is executed.
This is not entirely true because del_timer() can be invoked from interrupt
context and therefore hit in the middle of a running timer callback.
Contrary to that del_timer_sync() is not allowed to be invoked from
interrupt context unless the affected timer is marked with TIMER_IRQSAFE.
del_timer_sync() has proper checks in place to detect such a situation.
Give up on the UP optimization and make del_timer_sync() unconditionally
available.
Co-developed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/all/20220407161745.7d6754b3@gandalf.local.home
Link: https://lore.kernel.org/all/20221110064101.429013735@goodmis.org
---
include/linux/timer.h | 7 +------
kernel/time/timer.c | 2 --
2 files changed, 1 insertion(+), 8 deletions(-)
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -183,12 +183,7 @@ extern int timer_reduce(struct timer_lis
extern void add_timer(struct timer_list *timer);
extern int try_to_del_timer_sync(struct timer_list *timer);
-
-#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
- extern int del_timer_sync(struct timer_list *timer);
-#else
-# define del_timer_sync(t) del_timer(t)
-#endif
+extern int del_timer_sync(struct timer_list *timer);
extern void init_timers(void);
struct hrtimer;
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1392,7 +1392,6 @@ static inline void timer_sync_wait_runni
static inline void del_timer_wait_running(struct timer_list *timer) { }
#endif
-#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
/**
* del_timer_sync - Deactivate a timer and wait for the handler to finish.
* @timer: The timer to be deactivated
@@ -1473,7 +1472,6 @@ int del_timer_sync(struct timer_list *ti
return ret;
}
EXPORT_SYMBOL(del_timer_sync);
-#endif
static void call_timer_fn(struct timer_list *timer,
void (*fn)(struct timer_list *),
next prev parent reply other threads:[~2022-11-22 17:45 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-22 17:44 [patch V2 00/17] timers: Provide timer_shutdown[_sync]() Thomas Gleixner
2022-11-22 17:44 ` [patch V2 01/17] Documentation: Remove bogus claim about del_timer_sync() Thomas Gleixner
2022-11-22 17:44 ` [patch V2 02/17] ARM: spear: Do not use timer namespace for timer_shutdown() function Thomas Gleixner
2022-11-22 17:44 ` [patch V2 03/17] clocksource/drivers/arm_arch_timer: " Thomas Gleixner
2022-11-22 17:44 ` [patch V2 04/17] clocksource/drivers/sp804: " Thomas Gleixner
2022-11-22 17:44 ` [patch V2 05/17] timers: Get rid of del_singleshot_timer_sync() Thomas Gleixner
2022-11-22 17:44 ` [patch V2 06/17] timers: Replace BUG_ON()s Thomas Gleixner
2022-11-22 17:44 ` [patch V2 07/17] timers: Update kernel-doc for various functions Thomas Gleixner
2022-11-23 10:23 ` Anna-Maria Behnsen
2022-11-23 17:09 ` Thomas Gleixner
2022-11-22 17:44 ` Thomas Gleixner [this message]
2022-11-22 17:44 ` [patch V2 09/17] timers: Rename del_timer_sync() to timer_delete_sync() Thomas Gleixner
2022-11-22 22:23 ` David Laight
2022-11-22 22:45 ` Steven Rostedt
2022-11-23 0:08 ` Thomas Gleixner
2022-11-23 0:28 ` Steven Rostedt
2022-11-22 17:45 ` [patch V2 10/17] timers: Rename del_timer() to timer_delete() Thomas Gleixner
2022-11-22 17:45 ` [patch V2 11/17] Documentation: Replace del_timer/del_timer_sync() Thomas Gleixner
2022-11-22 17:45 ` [patch V2 12/17] timers: Silently ignore timers with a NULL function Thomas Gleixner
2022-11-23 9:22 ` Anna-Maria Behnsen
2022-11-23 10:39 ` Anna-Maria Behnsen
2022-11-23 11:06 ` Anna-Maria Behnsen
2022-11-23 17:08 ` Thomas Gleixner
2022-11-22 17:45 ` [patch V2 13/17] timers: Split [try_to_]del_timer[_sync]() to prepare for shutdown mode Thomas Gleixner
2022-11-22 23:04 ` Jacob Keller
2022-11-23 17:05 ` Thomas Gleixner
2022-11-23 18:45 ` Jacob Keller
2022-11-23 11:23 ` Anna-Maria Behnsen
2022-11-23 11:24 ` Anna-Maria Behnsen
2022-11-22 17:45 ` [patch V2 14/17] timers: Add shutdown mechanism to the internal functions Thomas Gleixner
2022-11-22 17:45 ` [patch V2 15/17] timers: Provide timer_shutdown[_sync]() Thomas Gleixner
2022-11-23 12:02 ` Anna-Maria Behnsen
2022-11-23 17:06 ` Thomas Gleixner
2022-11-22 17:45 ` [patch V2 16/17] timers: Update the documentation to reflect on the new timer_shutdown() API Thomas Gleixner
2022-11-22 17:45 ` [patch V2 17/17] Bluetooth: hci_qca: Fix the teardown problem for real Thomas Gleixner
2022-11-22 23:09 ` [patch V2 00/17] timers: Provide timer_shutdown[_sync]() Jacob Keller
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