[PATCH 1/1] net/hyperv: Use wait_event on outstanding sends during device removal

From: Haiyang Zhang
Date: Mon Jun 04 2012 - 10:57:09 EST


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

Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Reviewed-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>

---
drivers/net/hyperv/hyperv_net.h | 1 +
drivers/net/hyperv/netvsc.c | 12 ++++++------
2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 4ffcd57..2857ab0 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 8b91947..dee7b23e 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 ||
--
1.7.4.1

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