Re: [PATCH 2/3] coroutine-lock: introduce qemu_co_queue_enter_all

[Eric Blake]

On Wed, Apr 27, 2022 at 03:08:29PM +0200, Paolo Bonzini wrote:
> Because qemu_co_queue_restart_all does not release the lock, it should
> be used only in coroutine context.  Introduce a new function that,
> like qemu_co_enter_next, does release the lock, and use it whenever
> qemu_co_queue_restart_all was used outside coroutine context.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/qemu/coroutine.h   | 13 +++++++++++++
>  ui/console.c               |  2 +-
>  util/qemu-coroutine-lock.c |  7 +++++++
>  3 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
> index c23d41e1ff..e5954635f6 100644
> --- a/include/qemu/coroutine.h
> +++ b/include/qemu/coroutine.h
> @@ -234,6 +234,19 @@ void qemu_co_queue_restart_all(CoQueue *queue);
>      qemu_co_enter_next_impl(queue, QEMU_MAKE_LOCKABLE(lock))
>  bool qemu_co_enter_next_impl(CoQueue *queue, QemuLockable *lock);
>  
> +/**
> + * Empties the CoQueue, waking the waiting coroutine one at a time.  Unlike

maybe s/coroutine/coroutine(s)/

> + * qemu_co_queue_all, this function releases the lock during aio_co_wake
> + * because it is meant to be used outside coroutine context; in that case, 
> the
> + * coroutine is entered immediately, before qemu_co_enter_all returns.
> + *
> + * If used in coroutine context, qemu_co_enter_all is equivalent to
> + * qemu_co_queue_all.
> + */
> +#define qemu_co_enter_all(queue, lock) \
> +    qemu_co_enter_all_impl(queue, QEMU_MAKE_LOCKABLE(lock))
> +void qemu_co_enter_all_impl(CoQueue *queue, QemuLockable *lock);
> +

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org