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authorKevin Wolf <kwolf@redhat.com>2019-10-24 16:26:57 +0200
committerKevin Wolf <kwolf@redhat.com>2019-10-25 15:18:38 +0200
commit944f3d5dd216fcd8cb007eddd4f82dced0a15b3d (patch)
treed8befdc71c3b232d96476c60dd9ec2468dbc2b9d
parentc9b749d7bcaf035de4dc32cd6225a2ff51200d7b (diff)
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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 <kwolf@redhat.com> Tested-by: Michael Weiser <michael.weiser@gmx.de> Reviewed-by: Michael Weiser <michael.weiser@gmx.de> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Max Reitz <mreitz@redhat.com>
-rw-r--r--include/qemu/coroutine.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index 8d55663..dfd261c 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