linux-kernel - [PATCH 2/4] Drivers: hv: util: kvp: Fix a rescind processing issue

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Message-Id: <1482454443-10306-2-git-send-email-kys@exchange.microsoft.com>
Date:   Thu, 22 Dec 2016 16:54:01 -0800
From:   kys@...hange.microsoft.com
To:     gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
        devel@...uxdriverproject.org, olaf@...fle.de, apw@...onical.com,
        vkuznets@...hat.com, jasowang@...hat.com,
        leann.ogasawara@...onical.com
Cc:     "K. Y. Srinivasan" <kys@...rosoft.com>, <stable@...r.kernel.org>
Subject: [PATCH 2/4] Drivers: hv: util: kvp: Fix a rescind processing issue

From: K. Y. Srinivasan <kys@...rosoft.com>

KVP may use a char device to support the communication between
the user level daemon and the driver. When the KVP channel is rescinded
we need to make sure that the char device is fully cleaned up before
we can process a new KVP offer from the host. Implement this logic.

Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
Cc: <stable@...r.kernel.org>
---
 drivers/hv/hv_kvp.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index 5e1fdc8..3abfc59 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -88,6 +88,7 @@
 static const char kvp_devname[] = "vmbus/hv_kvp";
 static u8 *recv_buffer;
 static struct hvutil_transport *hvt;
+static struct completion release_event;
 /*
  * Register the kernel component with the user-level daemon.
  * As part of this registration, pass the LIC version number.
@@ -716,6 +717,7 @@ static void kvp_on_reset(void)
 	if (cancel_delayed_work_sync(&kvp_timeout_work))
 		kvp_respond_to_host(NULL, HV_E_FAIL);
 	kvp_transaction.state = HVUTIL_DEVICE_INIT;
+	complete(&release_event);
 }
 
 int
@@ -724,6 +726,7 @@ static void kvp_on_reset(void)
 	recv_buffer = srv->recv_buffer;
 	kvp_transaction.recv_channel = srv->channel;
 
+	init_completion(&release_event);
 	/*
 	 * When this driver loads, the user level daemon that
 	 * processes the host requests may not yet be running.
@@ -747,4 +750,5 @@ void hv_kvp_deinit(void)
 	cancel_delayed_work_sync(&kvp_timeout_work);
 	cancel_work_sync(&kvp_sendkey_work);
 	hvutil_transport_destroy(hvt);
+	wait_for_completion(&release_event);
 }
-- 
1.7.4.1