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[Qemu-block] [PATCH v2 04/13] io: Make qio_channel_yield() interruptible
From: |
Kevin Wolf |
Subject: |
[Qemu-block] [PATCH v2 04/13] io: Make qio_channel_yield() interruptible |
Date: |
Wed, 20 Feb 2019 18:48:34 +0100 |
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 <address@hidden>
---
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);
+ }
}
--
2.20.1
[Qemu-block] [PATCH v2 06/13] nbd: Move nbd_read_eof() to nbd/client.c, Kevin Wolf, 2019/02/20
[Qemu-block] [PATCH v2 07/13] nbd: Use low-level QIOChannel API in nbd_read_eof(), Kevin Wolf, 2019/02/20
[Qemu-block] [PATCH v2 10/13] block: Fix AioContext switch for drained node, Kevin Wolf, 2019/02/20
[Qemu-block] [PATCH v2 08/13] nbd: Increase bs->in_flight during AioContext switch, Kevin Wolf, 2019/02/20
[Qemu-block] [PATCH v2 11/13] test-bdrv-drain: AioContext switch in drained section, Kevin Wolf, 2019/02/20