linux-kernel - Re: [RFC PATCH 1/2] hv_netvsc: Split netvsc_revoke_buf() and netvsc_teardown

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Message-ID: <20180131150137.58abee5b@xeon-e3>
Date:   Wed, 31 Jan 2018 15:01:37 -0800
From:   Stephen Hemminger <stephen@...workplumber.org>
To:     Mohammed Gamal <mgamal@...hat.com>
Cc:     netdev@...r.kernel.org, otubo@...hat.com, sthemmin@...rosoft.com,
        haiyangz@...rosoft.com, linux-kernel@...r.kernel.org,
        devel@...uxdriverproject.org, vkuznets@...hat.com
Subject: Re: [RFC PATCH 1/2] hv_netvsc: Split netvsc_revoke_buf() and
 netvsc_teardown_gpadl()

On Wed, 31 Jan 2018 12:16:49 +0100
Mohammed Gamal <mgamal@...hat.com> wrote:

> On Tue, 2018-01-30 at 11:29 -0800, Stephen Hemminger wrote:
> > On Tue, 23 Jan 2018 10:34:04 +0100
> > Mohammed Gamal <mgamal@...hat.com> wrote:
> >   
> > > Split each of the functions into two for each of send/recv buffers
> > > 
> > > Signed-off-by: Mohammed Gamal <mgamal@...hat.com>  
> > 
> > Splitting these functions is not necessary  
> 
> How so? We need to send each message independently, and hence the split
> (see cover letter). Is there another way?

This is all that is needed.


Subject: [PATCH] hv_netvsc: work around for gpadl teardown on older windows
 server

On WS2012 the host ignores messages after vmbus channel is closed.
Workaround this by doing what Windows does and send the teardown
before close on older versions of NVSP protocol.

Reported-by: Mohammed Gamal <mgamal@...hat.com>
Fixes: 0cf737808ae7 ("hv_netvsc: netvsc_teardown_gpadl() split")
Signed-off-by: Stephen Hemminger <sthemmin@...rosoft.com>
---
 drivers/net/hyperv/netvsc.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 17e529af79dc..1a3df0eff42f 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -574,10 +574,17 @@ void netvsc_device_remove(struct hv_device *device)
 	 */
 	netdev_dbg(ndev, "net device safe to remove\n");
 
+	/* Workaround for older versions of Windows require that
+	 * buffer be revoked before channel is disabled
+	 */
+	if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_4)
+		netvsc_teardown_gpadl(device, net_device);
+
 	/* Now, we can close the channel safely */
 	vmbus_close(device->channel);
 
-	netvsc_teardown_gpadl(device, net_device);
+	if (net_device->nvsp_version >= NVSP_PROTOCOL_VERSION_4)
+		netvsc_teardown_gpadl(device, net_device);
 
 	/* And dissassociate NAPI context from device */
 	for (i = 0; i < net_device->num_chn; i++)
-- 
2.15.1