From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 5 Nov 2024 08:14:35 +0000 (+0100)
Subject: posix-cpu-timers: Use dedicated flag for CPU timer nanosleep
X-Git-Tag: v6.13-rc1~171^2~37
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4cf7bf2a2f1a8ace4a49a1138c8123fdb5990093;p=thirdparty%2Fkernel%2Flinux.git

posix-cpu-timers: Use dedicated flag for CPU timer nanosleep

POSIX CPU timer nanosleep creates a k_itimer on stack and uses the sigq
pointer to detect the nanosleep case in the expiry function.

Prepare for embedding sigqueue into struct k_itimer by using a dedicated
flag for nanosleep.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.238550394@linutronix.de
---

diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index b1de21731a082..bcd01208d7955 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -42,6 +42,7 @@ static inline int clockid_to_fd(const clockid_t clk)
  * @pid:	Pointer to target task PID
  * @elist:	List head for the expiry list
  * @firing:	Timer is currently firing
+ * @nanosleep:	Timer is used for nanosleep and is not a regular posix-timer
  * @handling:	Pointer to the task which handles expiry
  */
 struct cpu_timer {
@@ -50,6 +51,7 @@ struct cpu_timer {
 	struct pid			*pid;
 	struct list_head		elist;
 	bool				firing;
+	bool				nanosleep;
 	struct task_struct __rcu	*handling;
 };
 
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index a282a3c006054..0c441d8c26047 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -596,7 +596,7 @@ static void cpu_timer_fire(struct k_itimer *timer)
 
 	timer->it_status = POSIX_TIMER_DISARMED;
 
-	if (unlikely(timer->sigq == NULL)) {
+	if (unlikely(ctmr->nanosleep)) {
 		/*
 		 * This a special case for clock_nanosleep,
 		 * not a normal timer from sys_timer_create.
@@ -1493,6 +1493,7 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
 	timer.it_overrun = -1;
 	error = posix_cpu_timer_create(&timer);
 	timer.it_process = current;
+	timer.it.cpu.nanosleep = true;
 
 	if (!error) {
 		static struct itimerspec64 zero_it;