[patch V3 35/51] posix-cpu-timers: Use dedicated flag for CPU timer nanosleep

From: Thomas Gleixner
Date: Mon Jun 10 2024 - 12:49:51 EST


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@xxxxxxxxxxxxx>
---
include/linux/posix-timers.h | 4 +++-
kernel/time/posix-cpu-timers.c | 3 ++-
2 files changed, 5 insertions(+), 2 deletions(-)

--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -42,6 +42,7 @@ static inline int clockid_to_fd(const cl
* @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 {
@@ -49,7 +50,8 @@ struct cpu_timer {
struct timerqueue_head *head;
struct pid *pid;
struct list_head elist;
- int firing;
+ bool firing;
+ bool nanosleep;
struct task_struct __rcu *handling;
};

--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -588,7 +588,7 @@ static void cpu_timer_fire(struct k_itim

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.
@@ -1479,6 +1479,7 @@ static int do_cpu_nanosleep(const clocki
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;