On 18/02/19 17:18, Kevin Wolf wrote:
> Similar to how qemu_co_sleep_ns() allows to be preempted by an external
> coroutine entry, allow reentering qio_channel_yield() early.
>
> Signed-off-by: Kevin Wolf <kw...@redhat.com>
> ---
> include/io/channel.h | 9 ++++++---
> io/channel.c | 10 ++++++++++
> 2 files changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/include/io/channel.h b/include/io/channel.h
> index da2f138200..59460cb1ec 100644
> --- a/include/io/channel.h
> +++ b/include/io/channel.h
> @@ -739,10 +739,13 @@ void qio_channel_detach_aio_context(QIOChannel *ioc);
> * addition, no two coroutine can be waiting on the same condition
> * and channel at the same time.
> *
> - * This must only be called from coroutine context
> + * This must only be called from coroutine context. It is safe to
> + * reenter the coroutine externally while it is waiting; in this
> + * case the function will return even if @condition is not yet
> + * available.
> */
> -void qio_channel_yield(QIOChannel *ioc,
> - GIOCondition condition);
> +void coroutine_fn qio_channel_yield(QIOChannel *ioc,
> + GIOCondition condition);
>
> /**
> * qio_channel_wait:
> diff --git a/io/channel.c b/io/channel.c
> index 8dd0684f5d..303376e08d 100644
> --- a/io/channel.c
> +++ b/io/channel.c
> @@ -469,6 +469,16 @@ void coroutine_fn qio_channel_yield(QIOChannel *ioc,
> }
> qio_channel_set_aio_fd_handlers(ioc);
> qemu_coroutine_yield();
> +
> + /* Allow interrupting the operation by reentering the coroutine other
> than
> + * through the aio_fd_handlers. */
> + if (condition == G_IO_IN && ioc->read_coroutine) {
> + ioc->read_coroutine = NULL;
> + qio_channel_set_aio_fd_handlers(ioc);
> + } else if (condition == G_IO_OUT && ioc->write_coroutine) {
> + ioc->write_coroutine = NULL;
> + qio_channel_set_aio_fd_handlers(ioc);
> + }
> }
>
>
>
Perhaps it's a bit cleaner to remove the ioc->..._coroutine assignments,
and the call to qio_channel_set_aio_fd_handlers, from
qio_channel_restart_read and qio_channel_restart_write.
Paolo
