net/hyperv: Use wait_event on outstanding sends during device removal

Change the busy-waiting/udelay to wait_event on outstanding sends.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 7 insertions, 6 deletions

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 4ffcd57b011..2857ab078aa 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -478,6 +478,7 @@ struct netvsc_device {
         u32 nvsp_version;
 
         atomic_t num_outstanding_sends;
+        wait_queue_head_t wait_drain;
         bool start_remove;
         bool destroy;
         /*
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 8b919471472..0c569831db5 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -42,6 +42,7 @@ static struct netvsc_device *alloc_net_device(struct hv_device *device)
         if (!net_device)
                 return NULL;
 
+        init_waitqueue_head(&net_device->wait_drain);
         net_device->start_remove = false;
         net_device->destroy = false;
         net_device->dev = device;
@@ -387,12 +388,8 @@ int netvsc_device_remove(struct hv_device *device)
         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
 
         /* Wait for all send completions */
-        while (atomic_read(&net_device->num_outstanding_sends)) {
-                dev_info(&device->device,
-                        "waiting for %d requests to complete...\n",
-                        atomic_read(&net_device->num_outstanding_sends));
-                udelay(100);
-        }
+        wait_event(net_device->wait_drain,
+                   atomic_read(&net_device->num_outstanding_sends) == 0);
 
         netvsc_disconnect_vsp(net_device);
 
@@ -486,6 +483,9 @@ static void netvsc_send_completion(struct hv_device *device,
                 num_outstanding_sends =
                         atomic_dec_return(&net_device->num_outstanding_sends);
 
+                if (net_device->destroy && num_outstanding_sends == 0)
+                        wake_up(&net_device->wait_drain);
+
                 if (netif_queue_stopped(ndev) && !net_device->start_remove &&
                         (hv_ringbuf_avail_percent(&device->channel->outbound)
                         > RING_AVAIL_PERCENT_HIWATER ||