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[Qemu-devel] [PATCH v2 4/6] block: Quiesce old aio context during bdrv_s
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PATCH v2 4/6] block: Quiesce old aio context during bdrv_set_aio_context |
Date: |
Fri, 7 Apr 2017 14:54:12 +0800 |
The fact that the bs->aio_context is changing can confuse the dataplane
iothread, because of the now fine granularity aio context lock.
bdrv_drain should rather be a bdrv_drained_begin/end pair, but since
bs->aio_context is changing, we can just use aio_disable_external and
block_job_pause.
Reported-by: Ed Swierk <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Fam Zheng <address@hidden>
---
block.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/block.c b/block.c
index b8a3011..512515a 100644
--- a/block.c
+++ b/block.c
@@ -4396,11 +4396,14 @@ void bdrv_attach_aio_context(BlockDriverState *bs,
void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
{
- AioContext *ctx;
+ AioContext *ctx = bdrv_get_aio_context(bs);
+ aio_disable_external(ctx);
+ if (bs->job) {
+ block_job_pause(bs->job);
+ }
bdrv_drain(bs); /* ensure there are no in-flight requests */
- ctx = bdrv_get_aio_context(bs);
while (aio_poll(ctx, false)) {
/* wait for all bottom halves to execute */
}
@@ -4413,6 +4416,10 @@ void bdrv_set_aio_context(BlockDriverState *bs,
AioContext *new_context)
aio_context_acquire(new_context);
bdrv_attach_aio_context(bs, new_context);
aio_context_release(new_context);
+ if (bs->job) {
+ block_job_resume(bs->job);
+ }
+ aio_enable_external(ctx);
}
void bdrv_add_aio_context_notifier(BlockDriverState *bs,
--
2.9.3
[Qemu-devel] [PATCH v2 5/6] coroutine: Explicitly specify AioContext when entering coroutine, Fam Zheng, 2017/04/07