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signal: Replace resched_timer logic

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In preparation for handling ignored posix timer signals correctly and
embedding the sigqueue struct into struct k_itimer, hand down a pointer to
the sigqueue struct into posix_timer_deliver_signal() instead of just
having a boolean flag.

No functional change.

Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/all/20241105064213.652658158@linutronix.de
This commit is contained in:
Thomas Gleixner
2024-11-05 09:14:43 +01:00
parent 0360ed14d9
commit 11629b9808
3 changed files with 24 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
include/linux/posix-timers.h
View File

@@ -110,7 +110,7 @@ static inline void posix_cputimers_rt_watchdog(struct posix_cputimers *pct,
void posixtimer_rearm_itimer(struct task_struct *p);
bool posixtimer_init_sigqueue(struct sigqueue *q);
int posixtimer_send_sigqueue(struct k_itimer *tmr);
bool posixtimer_deliver_signal(struct kernel_siginfo *info);
bool posixtimer_deliver_signal(struct kernel_siginfo *info, struct sigqueue *timer_sigq);
void posixtimer_free_timer(struct k_itimer *timer);
/* Init task static initializer */
@@ -135,7 +135,8 @@ static inline void posix_cputimers_init(struct posix_cputimers *pct) { }
static inline void posix_cputimers_group_init(struct posix_cputimers *pct,
u64 cpu_limit) { }
static inline void posixtimer_rearm_itimer(struct task_struct *p) { }
static inline bool posixtimer_deliver_signal(struct kernel_siginfo *info) { return false; }
static inline bool posixtimer_deliver_signal(struct kernel_siginfo *info,
struct sigqueue *timer_sigq) { return false; }
static inline void posixtimer_free_timer(struct k_itimer *timer) { }
#endif

32
kernel/signal.c
View File

@@ -545,7 +545,7 @@ bool unhandled_signal(struct task_struct *tsk, int sig)
}
static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
bool *resched_timer)
struct sigqueue **timer_sigq)
{
struct sigqueue *q, *first = NULL;
@@ -568,10 +568,17 @@ still_pending:
list_del_init(&first->list);
copy_siginfo(info, &first->info);
*resched_timer = (first->flags & SIGQUEUE_PREALLOC) &&
(info->si_code == SI_TIMER);
__sigqueue_free(first);
/*
* posix-timer signals are preallocated and freed when the
* timer goes away. Either directly or by clearing
* SIGQUEUE_PREALLOC so that the next delivery will free
* them. Spare the extra round through __sigqueue_free()
* which is ignoring preallocated signals.
*/
if (unlikely((first->flags & SIGQUEUE_PREALLOC) && (info->si_code == SI_TIMER)))
*timer_sigq = first;
else
__sigqueue_free(first);
} else {
/*
* Ok, it wasn't in the queue. This must be
@@ -588,12 +595,12 @@ still_pending:
}
static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
kernel_siginfo_t *info, bool *resched_timer)
kernel_siginfo_t *info, struct sigqueue **timer_sigq)
{
int sig = next_signal(pending, mask);
if (sig)
collect_signal(sig, pending, info, resched_timer);
collect_signal(sig, pending, info, timer_sigq);
return sig;
}
@@ -605,18 +612,19 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
int dequeue_signal(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type)
{
struct task_struct *tsk = current;
bool resched_timer = false;
struct sigqueue *timer_sigq;
int signr;
lockdep_assert_held(&tsk->sighand->siglock);
again:
*type = PIDTYPE_PID;
signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
timer_sigq = NULL;
signr = __dequeue_signal(&tsk->pending, mask, info, &timer_sigq);
if (!signr) {
*type = PIDTYPE_TGID;
signr = __dequeue_signal(&tsk->signal->shared_pending,
mask, info, &resched_timer);
mask, info, &timer_sigq);
if (unlikely(signr == SIGALRM))
posixtimer_rearm_itimer(tsk);
@@ -642,8 +650,8 @@ again:
current->jobctl |= JOBCTL_STOP_DEQUEUED;
}
if (IS_ENABLED(CONFIG_POSIX_TIMERS) && unlikely(resched_timer)) {
if (!posixtimer_deliver_signal(info))
if (IS_ENABLED(CONFIG_POSIX_TIMERS) && unlikely(timer_sigq)) {
if (!posixtimer_deliver_signal(info, timer_sigq))
goto again;
}

2
kernel/time/posix-timers.c
View File

@@ -254,7 +254,7 @@ static void common_hrtimer_rearm(struct k_itimer *timr)
* This function is called from the signal delivery code. It decides
* whether the signal should be dropped and rearms interval timers.
*/
bool posixtimer_deliver_signal(struct kernel_siginfo *info)
bool posixtimer_deliver_signal(struct kernel_siginfo *info, struct sigqueue *timer_sigq)
{
struct k_itimer *timr;
unsigned long flags;