From 3284c3ddc48ba8fc853858c95d87dcc2ab160b29 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 16 Mar 2020 11:09:56 +0000 Subject: lockable: add lock guards This patch introduces two lock guard macros that automatically unlock a lock object (QemuMutex and others): void f(void) { QEMU_LOCK_GUARD(&mutex); if (!may_fail()) { return; /* automatically unlocks mutex */ } ... } and: WITH_QEMU_LOCK_GUARD(&mutex) { if (!may_fail()) { return; /* automatically unlocks mutex */ } } /* automatically unlocks mutex here */ ... Convert qemu-timer.c functions that benefit from these macros as an example. Manual qemu_mutex_lock/unlock() callers are left unmodified in cases where clarity would not improve by switching to the macros. Many other QemuMutex users remain in the codebase that might benefit from lock guards. Over time they can be converted, if that is desirable. Signed-off-by: Stefan Hajnoczi [Use QEMU_MAKE_LOCKABLE_NONNULL. - Paolo] Signed-off-by: Paolo Bonzini --- util/qemu-timer.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) (limited to 'util/qemu-timer.c') diff --git a/util/qemu-timer.c b/util/qemu-timer.c index ef52d28d37..d548d3c1ad 100644 --- a/util/qemu-timer.c +++ b/util/qemu-timer.c @@ -25,6 +25,7 @@ #include "qemu/osdep.h" #include "qemu/main-loop.h" #include "qemu/timer.h" +#include "qemu/lockable.h" #include "sysemu/replay.h" #include "sysemu/cpus.h" @@ -186,13 +187,12 @@ bool timerlist_expired(QEMUTimerList *timer_list) return false; } - qemu_mutex_lock(&timer_list->active_timers_lock); - if (!timer_list->active_timers) { - qemu_mutex_unlock(&timer_list->active_timers_lock); - return false; + WITH_QEMU_LOCK_GUARD(&timer_list->active_timers_lock) { + if (!timer_list->active_timers) { + return false; + } + expire_time = timer_list->active_timers->expire_time; } - expire_time = timer_list->active_timers->expire_time; - qemu_mutex_unlock(&timer_list->active_timers_lock); return expire_time <= qemu_clock_get_ns(timer_list->clock->type); } @@ -225,13 +225,12 @@ int64_t timerlist_deadline_ns(QEMUTimerList *timer_list) * value but ->notify_cb() is called when the deadline changes. Therefore * the caller should notice the change and there is no race condition. */ - qemu_mutex_lock(&timer_list->active_timers_lock); - if (!timer_list->active_timers) { - qemu_mutex_unlock(&timer_list->active_timers_lock); - return -1; + WITH_QEMU_LOCK_GUARD(&timer_list->active_timers_lock) { + if (!timer_list->active_timers) { + return -1; + } + expire_time = timer_list->active_timers->expire_time; } - expire_time = timer_list->active_timers->expire_time; - qemu_mutex_unlock(&timer_list->active_timers_lock); delta = expire_time - qemu_clock_get_ns(timer_list->clock->type); -- cgit v1.2.3-55-g7522