diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h index 9801e7f5a4..8d55663062 100644 --- a/include/qemu/coroutine.h +++ b/include/qemu/coroutine.h @@ -273,10 +273,29 @@ void qemu_co_rwlock_wrlock(CoRwlock *lock); */ void qemu_co_rwlock_unlock(CoRwlock *lock); +typedef struct QemuCoSleepState QemuCoSleepState; + /** - * Yield the coroutine for a given duration + * Yield the coroutine for a given duration. During this yield, @sleep_state + * (if not NULL) is set to an opaque pointer, which may be used for + * qemu_co_sleep_wake(). Be careful, the pointer is set back to zero when the + * timer fires. Don't save the obtained value to other variables and don't call + * qemu_co_sleep_wake from another aio context. */ -void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns); +void coroutine_fn qemu_co_sleep_ns_wakeable(QEMUClockType type, int64_t ns, + QemuCoSleepState **sleep_state); +static inline void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns) +{ + qemu_co_sleep_ns_wakeable(type, ns, NULL); +} + +/** + * Wake a coroutine if it is sleeping in qemu_co_sleep_ns. The timer will be + * deleted. @sleep_state must be the variable whose address was given to + * qemu_co_sleep_ns() and should be checked to be non-NULL before calling + * qemu_co_sleep_wake(). + */ +void qemu_co_sleep_wake(QemuCoSleepState *sleep_state); /** * Yield until a file descriptor becomes readable diff --git a/util/qemu-coroutine-sleep.c b/util/qemu-coroutine-sleep.c index 4bfdd30cbf..ae91b92b6e 100644 --- a/util/qemu-coroutine-sleep.c +++ b/util/qemu-coroutine-sleep.c @@ -17,31 +17,56 @@ #include "qemu/timer.h" #include "block/aio.h" -static void co_sleep_cb(void *opaque) -{ - Coroutine *co = opaque; +static const char *qemu_co_sleep_ns__scheduled = "qemu_co_sleep_ns"; +struct QemuCoSleepState { + Coroutine *co; + QEMUTimer *ts; + QemuCoSleepState **user_state_pointer; +}; + +void qemu_co_sleep_wake(QemuCoSleepState *sleep_state) +{ /* Write of schedule protected by barrier write in aio_co_schedule */ - atomic_set(&co->scheduled, NULL); - aio_co_wake(co); + const char *scheduled = atomic_cmpxchg(&sleep_state->co->scheduled, + qemu_co_sleep_ns__scheduled, NULL); + + assert(scheduled == qemu_co_sleep_ns__scheduled); + if (sleep_state->user_state_pointer) { + *sleep_state->user_state_pointer = NULL; + } + timer_del(sleep_state->ts); + aio_co_wake(sleep_state->co); } -void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns) +static void co_sleep_cb(void *opaque) +{ + qemu_co_sleep_wake(opaque); +} + +void coroutine_fn qemu_co_sleep_ns_wakeable(QEMUClockType type, int64_t ns, + QemuCoSleepState **sleep_state) { AioContext *ctx = qemu_get_current_aio_context(); - QEMUTimer *ts; - Coroutine *co = qemu_coroutine_self(); + QemuCoSleepState state = { + .co = qemu_coroutine_self(), + .ts = aio_timer_new(ctx, type, SCALE_NS, co_sleep_cb, &state), + .user_state_pointer = sleep_state, + }; - const char *scheduled = atomic_cmpxchg(&co->scheduled, NULL, __func__); + const char *scheduled = atomic_cmpxchg(&state.co->scheduled, NULL, + qemu_co_sleep_ns__scheduled); if (scheduled) { fprintf(stderr, "%s: Co-routine was already scheduled in '%s'\n", __func__, scheduled); abort(); } - ts = aio_timer_new(ctx, type, SCALE_NS, co_sleep_cb, co); - timer_mod(ts, qemu_clock_get_ns(type) + ns); + + if (sleep_state) { + *sleep_state = &state; + } + timer_mod(state.ts, qemu_clock_get_ns(type) + ns); qemu_coroutine_yield(); - timer_del(ts); - timer_free(ts); + timer_free(state.ts); }