From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:37150) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gyI4X-0008Tj-Uw for qemu-devel@nongnu.org; Mon, 25 Feb 2019 10:21:38 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gyI4T-0000lY-CH for qemu-devel@nongnu.org; Mon, 25 Feb 2019 10:21:37 -0500 From: Kevin Wolf Date: Mon, 25 Feb 2019 16:19:54 +0100 Message-Id: <20190225152053.15976-13-kwolf@redhat.com> In-Reply-To: <20190225152053.15976-1-kwolf@redhat.com> References: <20190225152053.15976-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 12/71] io: Make qio_channel_yield() interruptible List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Similar to how qemu_co_sleep_ns() allows preemption from an external coroutine entry, allow reentering qio_channel_yield() early. Signed-off-by: Kevin Wolf --- 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); =20 /** * 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 othe= r than + * through the aio_fd_handlers. */ + if (condition =3D=3D G_IO_IN && ioc->read_coroutine) { + ioc->read_coroutine =3D NULL; + qio_channel_set_aio_fd_handlers(ioc); + } else if (condition =3D=3D G_IO_OUT && ioc->write_coroutine) { + ioc->write_coroutine =3D NULL; + qio_channel_set_aio_fd_handlers(ioc); + } } =20 =20 --=20 2.20.1