netvsc: Deal with rescinded channels correctly

[ Upstream commit 73e64fa4 ]

We will not be able to send packets over a channel that has been
rescinded. Make necessary adjustments so we can properly cleanup
even when the channel is rescinded. This issue can be trigerred
in the NIC hot-remove path.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/hyperv/netvsc.c

@@ -151,6 +151,13 @@ static void netvsc_destroy_buf(struct hv_device *device)
 				       sizeof(struct nvsp_message),
 				       (unsigned long)revoke_packet,
 				       VM_PKT_DATA_INBAND, 0);
+		/* If the failure is because the channel is rescinded;
+		 * ignore the failure since we cannot send on a rescinded
+		 * channel. This would allow us to properly cleanup
+		 * even when the channel is rescinded.
+		 */
+		if (device->channel->rescind)
+			ret = 0;
 		/*
 		 * If we failed here, we might as well return and
 		 * have a leak rather than continue and a bugchk
@@ -211,6 +218,15 @@ static void netvsc_destroy_buf(struct hv_device *device)
 				       sizeof(struct nvsp_message),
 				       (unsigned long)revoke_packet,
 				       VM_PKT_DATA_INBAND, 0);
+
+		/* If the failure is because the channel is rescinded;
+		 * ignore the failure since we cannot send on a rescinded
+		 * channel. This would allow us to properly cleanup
+		 * even when the channel is rescinded.
+		 */
+		if (device->channel->rescind)
+			ret = 0;
+
 		/* If we failed here, we might as well return and
 		 * have a leak rather than continue and a bugchk
 		 */