linux-kernel - [PATCH 3.10 244/268] Drivers: hv: get rid of timeout in vmbus

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Date:   Mon, 19 Jun 2017 20:32:23 +0200
From:   Willy Tarreau <w@....eu>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        linux@...ck-us.net
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        "K . Y . Srinivasan" <kys@...rosoft.com>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Jiri Slaby <jslaby@...e.cz>, Willy Tarreau <w@....eu>
Subject: [PATCH 3.10 244/268] Drivers: hv: get rid of timeout in vmbus_open()

From: Vitaly Kuznetsov <vkuznets@...hat.com>

commit 396e287fa2ff46e83ae016cdcb300c3faa3b02f6 upstream.

vmbus_teardown_gpadl() can result in infinite wait when it is called on 5
second timeout in vmbus_open(). The issue is caused by the fact that gpadl
teardown operation won't ever succeed for an opened channel and the timeout
isn't always enough. As a guest, we can always trust the host to respond to
our request (and there is nothing we can do if it doesn't).

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
Signed-off-by: Sumit Semwal <sumit.semwal@...aro.org>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Signed-off-by: Willy Tarreau <w@....eu>
---
 drivers/hv/channel.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 90d6885..50e6ba9 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -114,7 +114,7 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
 	struct vmbus_channel_msginfo *open_info = NULL;
 	void *in, *out;
 	unsigned long flags;
-	int ret, t, err = 0;
+	int ret, err = 0;
 
 	newchannel->onchannel_callback = onchannelcallback;
 	newchannel->channel_callback_context = context;
@@ -204,11 +204,7 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
 		goto error1;
 	}
 
-	t = wait_for_completion_timeout(&open_info->waitevent, 5*HZ);
-	if (t == 0) {
-		err = -ETIMEDOUT;
-		goto error1;
-	}
+	wait_for_completion(&open_info->waitevent);
 
 
 	if (open_info->response.open_result.status)
-- 
2.8.0.rc2.1.gbe9624a