linux-kernel - [PATCH 3/5] posix-cpu-timers: Pass the task into arm

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Date:   Fri, 28 Feb 2020 11:09:46 -0600
From:   ebiederm@...ssion.com (Eric W. Biederman)
To:     <linux-kernel@...r.kernel.org>
Cc:     Oleg Nesterov <oleg@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 3/5] posix-cpu-timers: Pass the task into arm_timer


We have already had to compute the task to take siglock before
calling arm_timer.  So pass the benefit of that labor into arm_timer.

Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
 kernel/time/posix-cpu-timers.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 3b27710f9505..dbbfa88881a3 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -482,12 +482,11 @@ void posix_cpu_timers_exit_group(struct task_struct *tsk)
  * Insert the timer on the appropriate list before any timers that
  * expire later.  This must be called with the sighand lock held.
  */
-static void arm_timer(struct k_itimer *timer)
+static void arm_timer(struct k_itimer *timer, struct task_struct *p)
 {
 	int clkidx = CPUCLOCK_WHICH(timer->it_clock);
 	struct cpu_timer *ctmr = &timer->it.cpu;
 	u64 newexp = cpu_timer_getexpires(ctmr);
-	struct task_struct *p = ctmr->task;
 	struct posix_cputimer_base *base;
 
 	if (CPUCLOCK_PERTHREAD(timer->it_clock))
@@ -660,7 +659,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 	 */
 	cpu_timer_setexpires(ctmr, new_expires);
 	if (new_expires != 0 && val < new_expires) {
-		arm_timer(timer);
+		arm_timer(timer, p);
 	}
 
 	unlock_task_sighand(p, &flags);
@@ -981,7 +980,7 @@ static void posix_cpu_timer_rearm(struct k_itimer *timer)
 	/*
 	 * Now re-arm for the new expiry time.
 	 */
-	arm_timer(timer);
+	arm_timer(timer, p);
 	unlock_task_sighand(p, &flags);
 }
 
-- 
2.25.0