From: Sergio Lopez <slp@redhat.com>
To: qemu-block@nongnu.org
Cc: kwolf@redhat.com, qemu-devel@nongnu.org, Sergio Lopez <slp@redhat.com>
Subject: [Qemu-devel] [PATCH v2] nbd/server: attach client channel to the export's AioContext
Date: Thu, 12 Sep 2019 13:00:33 +0200 [thread overview]
Message-ID: <20190912110032.26395-1-slp@redhat.com> (raw)
On creation, the export's AioContext is set to the same one as the
BlockBackend, while the AioContext in the client QIOChannel is left
untouched.
As a result, when using data-plane, nbd_client_receive_next_request()
schedules coroutines in the IOThread AioContext, while the client's
QIOChannel is serviced from the main_loop, potentially triggering the
assertion at qio_channel_restart_[read|write].
To fix this, as soon we have the export corresponding to the client,
we call qio_channel_attach_aio_context() to attach the QIOChannel
context to the export's AioContext. This matches with the logic at
blk_aio_attached().
RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1748253
Signed-off-by: Sergio Lopez <slp@redhat.com>
---
Changelog
v2:
- Attach the channel once after negotiation completes, avoiding
duplication. (thanks Kevin Wolf).
---
nbd/server.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/nbd/server.c b/nbd/server.c
index 28c3c8be85..31d624e146 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1297,6 +1297,11 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
return ret;
}
+ /* Attach the channel to the same AioContext as the export */
+ if (client->exp && client->exp->ctx) {
+ qio_channel_attach_aio_context(client->ioc, client->exp->ctx);
+ }
+
assert(!client->optlen);
trace_nbd_negotiate_success();
--
2.21.0
next reply other threads:[~2019-09-12 11:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-12 11:00 Sergio Lopez [this message]
2019-09-20 12:38 ` [PATCH v2] nbd/server: attach client channel to the export's AioContext Eric Blake
2019-09-20 18:12 ` [Qemu-block] " John Snow
2019-09-20 18:49 ` John Snow
2019-09-20 19:11 ` Eric Blake
2019-09-20 22:03 ` Eric Blake
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