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ec8f954a40
Posix timer delete retry loops are affected by the same priority inversion
and live lock issues as the other timers.
Provide a RT specific synchronization function which keeps a reference to
the timer by holding rcu read lock to prevent the timer from being freed,
dropping the timer lock and invoking the timer specific wait function via a
new callback.
This does not yet cover posix CPU timers because they need more special
treatment on PREEMPT_RT.
[ This is folded into the original attempt which did not use a callback. ]
Originally-by: Anna-Maria Gleixenr <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190819143801.656864506@linutronix.de
43 lines
1.7 KiB
C
43 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#define TIMER_RETRY 1
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struct k_clock {
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int (*clock_getres)(const clockid_t which_clock,
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struct timespec64 *tp);
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int (*clock_set)(const clockid_t which_clock,
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const struct timespec64 *tp);
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int (*clock_get)(const clockid_t which_clock,
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struct timespec64 *tp);
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int (*clock_adj)(const clockid_t which_clock, struct __kernel_timex *tx);
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int (*timer_create)(struct k_itimer *timer);
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int (*nsleep)(const clockid_t which_clock, int flags,
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const struct timespec64 *);
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int (*timer_set)(struct k_itimer *timr, int flags,
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struct itimerspec64 *new_setting,
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struct itimerspec64 *old_setting);
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int (*timer_del)(struct k_itimer *timr);
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void (*timer_get)(struct k_itimer *timr,
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struct itimerspec64 *cur_setting);
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void (*timer_rearm)(struct k_itimer *timr);
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s64 (*timer_forward)(struct k_itimer *timr, ktime_t now);
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ktime_t (*timer_remaining)(struct k_itimer *timr, ktime_t now);
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int (*timer_try_to_cancel)(struct k_itimer *timr);
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void (*timer_arm)(struct k_itimer *timr, ktime_t expires,
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bool absolute, bool sigev_none);
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void (*timer_wait_running)(struct k_itimer *timr);
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};
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extern const struct k_clock clock_posix_cpu;
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extern const struct k_clock clock_posix_dynamic;
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extern const struct k_clock clock_process;
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extern const struct k_clock clock_thread;
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extern const struct k_clock alarm_clock;
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int posix_timer_event(struct k_itimer *timr, int si_private);
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void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting);
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int common_timer_set(struct k_itimer *timr, int flags,
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struct itimerspec64 *new_setting,
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struct itimerspec64 *old_setting);
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int common_timer_del(struct k_itimer *timer);
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