hv_netvsc: netvsc_teardown_gpadl() split

It was found that in some cases host refuses to teardown GPADL for send/
receive buffers (probably when some work with these buffere is scheduled or
ongoing). Change the teardown logic to be:
1) Send NVSP_MSG1_TYPE_REVOKE_* messages
2) Close the channel
3) Teardown GPADLs.
This seems to work reliably.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 5bb6a20072dd724beab2c8f22f458d01018fc3d5..bfc79698b8f4116564d14391527a866d5043ab00 100644 (file)
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -100,12 +100,11 @@ static void free_netvsc_device_rcu(struct netvsc_device *nvdev)
        call_rcu(&nvdev->rcu, free_netvsc_device);
 }
 
-static void netvsc_destroy_buf(struct hv_device *device)
+static void netvsc_revoke_buf(struct hv_device *device,
+                             struct netvsc_device *net_device)
 {
        struct nvsp_message *revoke_packet;
        struct net_device *ndev = hv_get_drvdata(device);
-       struct net_device_context *ndc = netdev_priv(ndev);
-       struct netvsc_device *net_device = rtnl_dereference(ndc->nvdev);
        int ret;
 
        /*
@@ -148,28 +147,6 @@ static void netvsc_destroy_buf(struct hv_device *device)
                net_device->recv_section_cnt = 0;
        }
 
-       /* Teardown the gpadl on the vsp end */
-       if (net_device->recv_buf_gpadl_handle) {
-               ret = vmbus_teardown_gpadl(device->channel,
-                                          net_device->recv_buf_gpadl_handle);
-
-               /* If we failed here, we might as well return and have a leak
-                * rather than continue and a bugchk
-                */
-               if (ret != 0) {
-                       netdev_err(ndev,
-                                  "unable to teardown receive buffer's gpadl\n");
-                       return;
-               }
-               net_device->recv_buf_gpadl_handle = 0;
-       }
-
-       if (net_device->recv_buf) {
-               /* Free up the receive buffer */
-               vfree(net_device->recv_buf);
-               net_device->recv_buf = NULL;
-       }
-
        /* Deal with the send buffer we may have setup.
         * If we got a  send section size, it means we received a
         * NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE msg (ie sent
@@ -210,7 +187,35 @@ static void netvsc_destroy_buf(struct hv_device *device)
                }
                net_device->send_section_cnt = 0;
        }
-       /* Teardown the gpadl on the vsp end */
+}
+
+static void netvsc_teardown_gpadl(struct hv_device *device,
+                                 struct netvsc_device *net_device)
+{
+       struct net_device *ndev = hv_get_drvdata(device);
+       int ret;
+
+       if (net_device->recv_buf_gpadl_handle) {
+               ret = vmbus_teardown_gpadl(device->channel,
+                                          net_device->recv_buf_gpadl_handle);
+
+               /* If we failed here, we might as well return and have a leak
+                * rather than continue and a bugchk
+                */
+               if (ret != 0) {
+                       netdev_err(ndev,
+                                  "unable to teardown receive buffer's gpadl\n");
+                       return;
+               }
+               net_device->recv_buf_gpadl_handle = 0;
+       }
+
+       if (net_device->recv_buf) {
+               /* Free up the receive buffer */
+               vfree(net_device->recv_buf);
+               net_device->recv_buf = NULL;
+       }
+
        if (net_device->send_buf_gpadl_handle) {
                ret = vmbus_teardown_gpadl(device->channel,
                                           net_device->send_buf_gpadl_handle);
@@ -420,7 +425,8 @@ static int netvsc_init_buf(struct hv_device *device,
        goto exit;
 
 cleanup:
-       netvsc_destroy_buf(device);
+       netvsc_revoke_buf(device, net_device);
+       netvsc_teardown_gpadl(device, net_device);
 
 exit:
        return ret;
@@ -539,11 +545,6 @@ cleanup:
        return ret;
 }
 
-static void netvsc_disconnect_vsp(struct hv_device *device)
-{
-       netvsc_destroy_buf(device);
-}
-
 /*
  * netvsc_device_remove - Callback when the root bus device is removed
  */
@@ -557,7 +558,7 @@ void netvsc_device_remove(struct hv_device *device)
 
        cancel_work_sync(&net_device->subchan_work);
 
-       netvsc_disconnect_vsp(device);
+       netvsc_revoke_buf(device, net_device);
 
        RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
 
@@ -570,6 +571,8 @@ void netvsc_device_remove(struct hv_device *device)
        /* Now, we can close the channel safely */
        vmbus_close(device->channel);
 
+       netvsc_teardown_gpadl(device, net_device);
+
        /* And dissassociate NAPI context from device */
        for (i = 0; i < net_device->num_chn; i++)
                netif_napi_del(&net_device->chan_table[i].napi);