[patch 10/45] posix-cpu-timers: Use @now instead of @val for clarity

From: Thomas Gleixner
Date: Tue Jun 06 2023 - 10:38:10 EST


posix_cpu_timer_set() uses @val as variable for the current time. That's
confusing at best.

Use @now as anywhere else and rewrite the confusing comment about clock
sampling.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/time/posix-cpu-timers.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)

--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -620,7 +620,7 @@ static int posix_cpu_timer_set(struct k_
{
bool sigev_none = timer->it_sigev_notify == SIGEV_NONE;
clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
- u64 old_expires, new_expires, old_incr, val;
+ u64 old_expires, new_expires, old_incr, now;
struct cpu_timer *ctmr = &timer->it.cpu;
struct sighand_struct *sighand;
struct task_struct *p;
@@ -672,17 +672,13 @@ static int posix_cpu_timer_set(struct k_
}

/*
- * We need to sample the current value to convert the new
- * value from to relative and absolute, and to convert the
- * old value from absolute to relative. To set a process
- * timer, we need a sample to balance the thread expiry
- * times (in arm_timer). With an absolute time, we must
- * check if it's already passed. In short, we need a sample.
+ * Sample the current clock for saving the previous setting
+ * and for rearming the timer.
*/
if (CPUCLOCK_PERTHREAD(timer->it_clock))
- val = cpu_clock_sample(clkid, p);
+ now = cpu_clock_sample(clkid, p);
else
- val = cpu_clock_sample_group(clkid, p, !sigev_none);
+ now = cpu_clock_sample_group(clkid, p, !sigev_none);

if (old) {
if (old_expires == 0) {
@@ -696,10 +692,10 @@ static int posix_cpu_timer_set(struct k_
* though we are swallowing that pending
* notification here to install the new setting.
*/
- u64 exp = bump_cpu_timer(timer, val);
+ u64 exp = bump_cpu_timer(timer, now);

- if (val < exp) {
- old_expires = exp - val;
+ if (now < exp) {
+ old_expires = exp - now;
old->it_value = ns_to_timespec64(old_expires);
} else {
old->it_value.tv_nsec = 1;
@@ -721,7 +717,7 @@ static int posix_cpu_timer_set(struct k_

/* Convert relative expiry time to absolute */
if (new_expires && !(timer_flags & TIMER_ABSTIME))
- new_expires += val;
+ new_expires += now;

/* Set the new expiry time (might be 0) */
cpu_timer_setexpires(ctmr, new_expires);
@@ -731,7 +727,7 @@ static int posix_cpu_timer_set(struct k_
* not yet expired and the timer requires signal delivery.
* SIGEV_NONE timers are never armed.
*/
- if (!sigev_none && new_expires && val < new_expires)
+ if (!sigev_none && new_expires && now < new_expires)
arm_timer(timer, p);

unlock_task_sighand(p, &flags);
@@ -751,7 +747,7 @@ static int posix_cpu_timer_set(struct k_
timer->it_overrun_last = 0;
timer->it_overrun = -1;

- if (!sigev_none && val >= new_expires) {
+ if (!sigev_none && now >= new_expires) {
if (new_expires != 0) {
/*
* The designated time already passed, so we notify