From 944f3d5dd216fcd8cb007eddd4f82dced0a15b3d Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Thu, 24 Oct 2019 16:26:57 +0200 Subject: [PATCH] coroutine: Add qemu_co_mutex_assert_locked() Some functions require that the caller holds a certain CoMutex for them to operate correctly. Add a function so that they can assert the lock is really held. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf Tested-by: Michael Weiser Reviewed-by: Michael Weiser Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Denis V. Lunev Reviewed-by: Max Reitz --- include/qemu/coroutine.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h index 8d55663062..dfd261c5b1 100644 --- a/include/qemu/coroutine.h +++ b/include/qemu/coroutine.h @@ -167,6 +167,21 @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex); */ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex); +/** + * Assert that the current coroutine holds @mutex. + */ +static inline coroutine_fn void qemu_co_mutex_assert_locked(CoMutex *mutex) +{ + /* + * mutex->holder doesn't need any synchronisation if the assertion holds + * true because the mutex protects it. If it doesn't hold true, we still + * don't mind if another thread takes or releases mutex behind our back, + * because the condition will be false no matter whether we read NULL or + * the pointer for any other coroutine. + */ + assert(atomic_read(&mutex->locked) && + mutex->holder == qemu_coroutine_self()); +} /** * CoQueues are a mechanism to queue coroutines in order to continue executing