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href="https://git.kernel.org/tip/50f53b23f1e3fae071381af9a15ac1028c4efc42">https://git.kernel.org/tip/50f53b23f1e3fae071381af9a15ac1028c4efc42</a> Author: Thomas Gleixner <tglx@linutronix.de> AuthorDate: Sat, 08 Mar 2025 17:48:30 +01:00 Committer: Thomas Gleixner <tglx@linutronix.de> CommitterDate: Thu, 13 Mar 2025 12:07:17 +01:00 posix-timers: Simplify lock/unlock_timer() Since the integration of sigqueue into the timer struct, lock_timer() is only used in task context. So taking the lock with irqsave() is not longer required. Convert it to use spin_[un]lock_irq(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: <a href="https://lore.kernel.org/all/20250308155623.959825668@linutronix.de">https://lore.kernel.org/all/20250308155623.959825668@linutronix.de</a> --- kernel/time/posix-timers.c | 70 +++++++++++++++---------------------- 1 file changed, 29 insertions(+), 41 deletions(-) diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index 988cbfb..4d25bea 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -53,14 +53,19 @@ static const struct k_clock clock_realtime, clock_monotonic; #error "SIGEV_THREAD_ID must not share bit with other SIGEV values!" #endif -static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags); +static struct k_itimer *__lock_timer(timer_t timer_id); -#define lock_timer(tid, flags) \ -({ struct k_itimer *__timr; \ - __cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags)); \ - __timr; \ +#define lock_timer(tid) \ +({ struct k_itimer *__timr; \ + __cond_lock(&__timr->it_lock, __timr = __lock_timer(tid)); \ + __timr; \ }) +static inline void unlock_timer(struct k_itimer *timr) +{ + spin_unlock_irq(&timr->it_lock); +} + static int hash(struct signal_struct *sig, unsigned int nr) { return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable)); @@ -144,11 +149,6 @@ static int posix_timer_add(struct k_itimer *timer) return -EAGAIN; } -static inline void unlock_timer(struct k_itimer *timr, unsigned long flags) -{ - spin_unlock_irqrestore(&timr->it_lock, flags); -} - static int posix_get_realtime_timespec(clockid_t which_clock, struct timespec64 *tp) { ktime_get_real_ts64(tp); @@ -538,7 +538,7 @@ COMPAT_SYSCALL_DEFINE3(timer_create, clockid_t, which_clock, } #endif -static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags) +static struct k_itimer *__lock_timer(timer_t timer_id) { struct k_itimer *timr; @@ -580,14 +580,14 @@ static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags) guard(rcu)(); timr = posix_timer_by_id(timer_id); if (timr) { - spin_lock_irqsave(&timr->it_lock, *flags); + spin_lock_irq(&timr->it_lock); /* * Validate under timr::it_lock that timr::it_signal is * still valid. Pairs with #1 above. */ if (timr->it_signal == current->signal) return timr; - spin_unlock_irqrestore(&timr->it_lock, *flags); + spin_unlock_irq(&timr->it_lock); } return NULL; } @@ -680,17 +680,16 @@ void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting) static int do_timer_gettime(timer_t timer_id, struct itimerspec64 *setting) { struct k_itimer *timr; - unsigned long flags; int ret = 0; - timr = lock_timer(timer_id, &flags); + timr = lock_timer(timer_id); if (!timr) return -EINVAL; memset(setting, 0, sizeof(*setting)); timr->kclock->timer_get(timr, setting); - unlock_timer(timr, flags); + unlock_timer(timr); return ret; } @@ -746,15 +745,14 @@ SYSCALL_DEFINE2(timer_gettime32, timer_t, timer_id, SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id) { struct k_itimer *timr; - unsigned long flags; int overrun; - timr = lock_timer(timer_id, &flags); + timr = lock_timer(timer_id); if (!timr) return -EINVAL; overrun = timer_overrun_to_int(timr); - unlock_timer(timr, flags); + unlock_timer(timr); return overrun; } @@ -813,14 +811,13 @@ static void common_timer_wait_running(struct k_itimer *timer) * when the task which tries to delete or disarm the timer has preempted * the task which runs the expiry in task work context. */ -static struct k_itimer *timer_wait_running(struct k_itimer *timer, - unsigned long *flags) +static struct k_itimer *timer_wait_running(struct k_itimer *timer) { timer_t timer_id = READ_ONCE(timer->it_id); /* Prevent kfree(timer) after dropping the lock */ scoped_guard (rcu) { - unlock_timer(timer, *flags); + unlock_timer(timer); /* * kc->timer_wait_running() might drop RCU lock. So @timer * cannot be touched anymore after the function returns! @@ -829,7 +826,7 @@ static struct k_itimer *timer_wait_running(struct k_itimer *timer, } /* Relock the timer. It might be not longer hashed. */ - return lock_timer(timer_id, flags); + return lock_timer(timer_id); } /* @@ -889,7 +886,6 @@ static int do_timer_settime(timer_t timer_id, int tmr_flags, struct itimerspec64 *old_spec64) { struct k_itimer *timr; - unsigned long flags; int error; if (!timespec64_valid(&new_spec64->it_interval) || @@ -899,7 +895,7 @@ static int do_timer_settime(timer_t timer_id, int tmr_flags, if (old_spec64) memset(old_spec64, 0, sizeof(*old_spec64)); - timr = lock_timer(timer_id, &flags); + timr = lock_timer(timer_id); retry: if (!timr) return -EINVAL; @@ -916,10 +912,10 @@ retry: // We already got the old time... old_spec64 = NULL; /* Unlocks and relocks the timer if it still exists */ - timr = timer_wait_running(timr, &flags); + timr = timer_wait_running(timr); goto retry; } - unlock_timer(timr, flags); + unlock_timer(timr); return error; } @@ -995,10 +991,7 @@ static inline void posix_timer_cleanup_ignored(struct k_itimer *tmr) /* Delete a POSIX.1b interval timer. */ SYSCALL_DEFINE1(timer_delete, timer_t, timer_id) { - struct k_itimer *timer; - unsigned long flags; - - timer = lock_timer(timer_id, &flags); + struct k_itimer *timer = lock_timer(timer_id); retry_delete: if (!timer) @@ -1009,7 +1002,7 @@ retry_delete: if (unlikely(timer->kclock->timer_del(timer) == TIMER_RETRY)) { /* Unlocks and relocks the timer if it still exists */ - timer = timer_wait_running(timer, &flags); + timer = timer_wait_running(timer); goto retry_delete; } @@ -1028,7 +1021,7 @@ retry_delete: WRITE_ONCE(timer->it_signal, NULL); } - unlock_timer(timer, flags); + unlock_timer(timer); posix_timer_unhash_and_free(timer); return 0; } @@ -1039,12 +1032,7 @@ retry_delete: */ static void itimer_delete(struct k_itimer *timer) { - unsigned long flags; - - /* - * irqsave is required to make timer_wait_running() work. - */ - spin_lock_irqsave(&timer->it_lock, flags); + spin_lock_irq(&timer->it_lock); retry_delete: /* @@ -1065,7 +1053,7 @@ retry_delete: * do_exit() only for the last thread of the thread group. * So no other task can access and delete that timer. */ - if (WARN_ON_ONCE(timer_wait_running(timer, &flags) != timer)) + if (WARN_ON_ONCE(timer_wait_running(timer) != timer)) return; goto retry_delete; @@ -1082,7 +1070,7 @@ retry_delete: */ WRITE_ONCE(timer->it_signal, NULL); - spin_unlock_irqrestore(&timer->it_lock, flags); + spin_unlock_irq(&timer->it_lock); posix_timer_unhash_and_free(timer); } </pre></td><td width="32" rowspan="2" class="c" valign="top"><img src="/images/icornerr.gif" width="32" height="32" alt="\" /></td></tr><tr><td align="right" valign="bottom"> 聽 </td></tr><tr><td align="right" valign="bottom">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerl.gif" width="32" height="32" alt="\" /></td><td class="c">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerr.gif" width="32" height="32" alt="/" /></td></tr><tr><td align="right" valign="top" colspan="2"> 聽 </td><td class="lm">Last update: 2025-03-13 12:33 聽聽 [W:0.342 / U:2.714 seconds] 漏2003-2020 <a href="http://blog.jasper.es/">Jasper Spaans</a>|hosted at <a href="https://www.digitalocean.com/?refcode=9a8e99d24cf9">Digital Ocean</a> and my Meterkast|<a href="http://blog.jasper.es/categories.html#lkml-ref">Read the blog</a></td><td>聽</td></tr></table><script language="javascript" src="/js/styleswitcher.js" type="text/javascript"></script></body></html>