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>

1 files changed, 1 insertions, 1 deletions

diff --git a/block/io.c b/block/io.c
index 9769ec53b0..789e6373d5 100644
--- a/block/io.c
+++ b/block/io.c
@@ -751,7 +751,7 @@ void bdrv_drain_all(void)
  *
  * This function should be called when a tracked request is completing.
  */
-static void tracked_request_end(BdrvTrackedRequest *req)
+static void coroutine_fn tracked_request_end(BdrvTrackedRequest *req)
 {
     if (req->serialising) {
         qatomic_dec(&req->bs->serialising_in_flight);