linux-kernel - [RFC PATCH 03/10] posix-timers: Cleanup reaped target handling

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Date:	Sat, 12 Oct 2013 21:06:19 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Kosaki Motohiro <kosaki.motohiro@...fujitsu.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [RFC PATCH 03/10] posix-timers: Cleanup reaped target handling

When a timer's target is seen to be buried, for example on calls
to timer_gettime(), the posix cpu timers code behaves a bit
like a garbage collector and releases early the reference to the
task.

Then again, this optimization complicates the code for no much
value: it's up to the user to release the timer and its associated
ressources by calling timer_delete() after it buries the target
tasks.

Remove this to simplify the code.

Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Kosaki Motohiro <kosaki.motohiro@...fujitsu.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
---
 kernel/posix-cpu-timers.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index dd75dc4..f509f53 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -638,8 +638,6 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
 	 */
 	if (unlikely(p->sighand == NULL)) {
 		read_unlock(&tasklist_lock);
-		put_task_struct(p);
-		timer->it.cpu.task = NULL;
 		return -ESRCH;
 	}
 
@@ -807,8 +805,6 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 			 * We can't even collect a sample any more.
 			 * Call the timer disarmed, nothing else to do.
 			 */
-			put_task_struct(p);
-			timer->it.cpu.task = NULL;
 			timer->it.cpu.expires = 0;
 			read_unlock(&tasklist_lock);
 			goto dead;
@@ -1058,8 +1054,6 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
 			 * The process has been reaped.
 			 * We can't even collect a sample any more.
 			 */
-			put_task_struct(p);
-			timer->it.cpu.task = p = NULL;
 			timer->it.cpu.expires = 0;
 			goto out_unlock;
 		} else if (unlikely(p->exit_state) && thread_group_empty(p)) {
-- 
1.8.3.1

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