From: Dexuan Cui <decui@microsoft.com>
To: kys@microsoft.com, haiyangz@microsoft.com,
sthemmin@microsoft.com, sashal@kernel.org,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
mikelley@microsoft.com, Alexander.Levin@microsoft.com
Cc: sunilmut@microsoft.com, Andrea.Parri@microsoft.com,
Dexuan Cui <decui@microsoft.com>
Subject: [PATCH] Drivers: hv: vmbus: Ignore CHANNELMSG_TL_CONNECT_RESULT(23)
Date: Thu, 9 Jan 2020 17:25:15 -0800 [thread overview]
Message-ID: <1578619515-115811-1-git-send-email-decui@microsoft.com> (raw)
When a Linux hv_sock app tries to connect to a Service GUID on which no
host app is listening, a recent host (RS3+) sends a
CHANNELMSG_TL_CONNECT_RESULT (23) message to Linux and this triggers such
a warning:
unknown msgtype=23
WARNING: CPU: 2 PID: 0 at drivers/hv/vmbus_drv.c:1031 vmbus_on_msg_dpc
Actually Linux can safely ignore the message because the Linux app's
connect() will time out in 2 seconds: see VSOCK_DEFAULT_CONNECT_TIMEOUT
and vsock_stream_connect(). We don't bother to make use of the message
because: 1) it's only supported on recent hosts; 2) a non-trivial effort
is required to use the message in Linux, but the benefit is small.
So, let's not see the warning by silently ignoring the message.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
drivers/hv/vmbus_drv.c | 5 +++++
include/linux/hyperv.h | 2 ++
2 files changed, 7 insertions(+)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 4ef5a66df680..c838b6f5f726 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1033,6 +1033,11 @@ void vmbus_on_msg_dpc(unsigned long data)
}
entry = &channel_message_table[hdr->msgtype];
+
+ /* Linux ignores some messages, e.g. CHANNELMSG_TL_CONNECT_RESULT. */
+ if (!entry->message_handler)
+ goto msg_handled;
+
if (entry->handler_type == VMHT_BLOCKING) {
ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
if (ctx == NULL)
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 26f3aeeae1ca..41c58011431e 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -425,6 +425,8 @@ enum vmbus_channel_message_type {
CHANNELMSG_19 = 19,
CHANNELMSG_20 = 20,
CHANNELMSG_TL_CONNECT_REQUEST = 21,
+ CHANNELMSG_22 = 22,
+ CHANNELMSG_TL_CONNECT_RESULT = 23,
CHANNELMSG_COUNT
};
--
2.19.1
next reply other threads:[~2020-01-10 1:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 1:25 Dexuan Cui [this message]
2020-01-18 17:29 ` [PATCH] Drivers: hv: vmbus: Ignore CHANNELMSG_TL_CONNECT_RESULT(23) Michael Kelley
2020-01-19 23:35 ` Dexuan Cui
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1578619515-115811-1-git-send-email-decui@microsoft.com \
--to=decui@microsoft.com \
--cc=Alexander.Levin@microsoft.com \
--cc=Andrea.Parri@microsoft.com \
--cc=haiyangz@microsoft.com \
--cc=kys@microsoft.com \
--cc=linux-hyperv@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mikelley@microsoft.com \
--cc=sashal@kernel.org \
--cc=sthemmin@microsoft.com \
--cc=sunilmut@microsoft.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).