The patch virtio_net: limit xmit polling
got the logic reversed: it polled while we had
capacity not while ring was empty.
Fix it up and clean up a bit by using a for loop.
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
OK, turns out that patch was borken. Here's
a fix that survived stress test on my box.
Pushed on my branch, I'll send a rebased series
with Rusty's comments addressed ASAP.
drivers/net/virtio_net.c | 10 ++++++----
1 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 9982bd7..c8cd22d 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -514,12 +514,14 @@ static bool free_old_xmit_skbs(struct virtnet_info *vi, int capacity)
struct sk_buff *skb;
unsigned int len;
bool c;
+ int n;
+
/* We try to free up at least 2 skbs per one sent, so that we'll get
* all of the memory back if they are used fast enough. */
- int n = 2;
-
- while ((c = virtqueue_get_capacity(vi->svq) >= capacity) && --n > 0 &&
- (skb = virtqueue_get_buf(vi->svq, &len)) != NULL) {
+ for (n = 0;
+ ((c = virtqueue_get_capacity(vi->svq)) < capacity || n < 2) &&
+ ((skb = virtqueue_get_buf(vi->svq, &len)));
+ ++n) {
pr_debug("Sent skb %p\n", skb);
vi->dev->stats.tx_bytes += skb->len;
vi->dev->stats.tx_packets++;
--
1.7.5.53.gc233e
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