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authorPaolo Bonzini <pbonzini@redhat.com>2022-04-27 15:08:30 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2022-05-12 12:29:44 +0200
commitf0d43b1ecef04105e0d0f55658182510b4e0f58e (patch)
tree4111e660ac9f48f89b00e440332dcbc8891b088f /util
parentd6ee15adec5a2345e88c680cd15ed48796c89c14 (diff)
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coroutine-lock: qemu_co_queue_restart_all is a coroutine-only qemu_co_enter_all
qemu_co_queue_restart_all is basically the same as qemu_co_enter_all but without a QemuLockable argument. That's perfectly fine, but only as long as the function is marked coroutine_fn. If used outside coroutine context, qemu_co_queue_wait will attempt to take the lock and that is just broken: if you are calling qemu_co_queue_restart_all outside coroutine context, the lock is going to be a QemuMutex which cannot be taken twice by the same thread. The patch adds the marker to qemu_co_queue_restart_all and to its sole non-coroutine_fn caller; it then reimplements the function in terms of qemu_co_enter_all_impl, to remove duplicated code and to clarify that the latter also works in coroutine context. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20220427130830.150180-4-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'util')
-rw-r--r--util/qemu-coroutine-lock.c21
1 files changed, 6 insertions, 15 deletions
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index 5b0342f..9ad24ab 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -67,21 +67,6 @@ void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock)
}
}
-void qemu_co_queue_restart_all(CoQueue *queue)
-{
- Coroutine *next;
-
- if (QSIMPLEQ_EMPTY(&queue->entries)) {
- return false;
- }
-
- while ((next = QSIMPLEQ_FIRST(&queue->entries)) != NULL) {
- QSIMPLEQ_REMOVE_HEAD(&queue->entries, co_queue_next);
- aio_co_wake(next);
- }
- return true;
-}
-
bool qemu_co_enter_next_impl(CoQueue *queue, QemuLockable *lock)
{
Coroutine *next;
@@ -115,6 +100,12 @@ void qemu_co_enter_all_impl(CoQueue *queue, QemuLockable *lock)
}
}
+void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue)
+{
+ /* No unlock/lock needed in coroutine context. */
+ qemu_co_enter_all_impl(queue, NULL);
+}
+
bool qemu_co_queue_empty(CoQueue *queue)
{
return QSIMPLEQ_FIRST(&queue->entries) == NULL;