From 6886ceaf61c2399419258246a064485e9b1e51ac Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 18 Feb 2019 14:09:32 +0100 Subject: [PATCH] io: Make qio_channel_yield() interruptible 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); /** * 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); + } }