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Date: Tue, 3 Apr 2012 21:23:55 +0200
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Subject: Re: [GIT] Networking
From: Torsten Kaiser <just.for.lkml@googlemail.com>
To: David Miller <davem@davemloft.net>
Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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On Tue, Apr 3, 2012 at 2:34 AM, David Miller <davem@davemloft.net> wrote:
> 7) virtio_net accidently uses net_ratelimit() not only on the kernel
>   warning but also the statistic bump, fix from Rick Jones.

I just saw this commit land in Linus tree and I think its got its
parentheses wrong.

Old code (minus the dev_warn()-messages):
if (net_ratelimit()) {
  if (likely(capacity == -ENOMEM)) {
    dev_warn(...);
  } else {
    dev->stats.tx_fifo_errors++;
    dev_warn(...);
  }
}

New code (minus the dev_warn()-messages):
if (likely(capacity == -ENOMEM)) {
  if (net_ratelimit()) {
    dev_warn(...);
  } else {
    dev->stats.tx_fifo_errors++;
    if (net_ratelimit())
      dev_warn(...);
  }
}

Now it will count -ENOMEM errors that were not logged..

I think, intended was:
if (likely(capacity == -ENOMEM)) {
  if (net_ratelimit()) {
    dev_warn(...);
  }
} else {
  dev->stats.tx_fifo_errors++;
  if (net_ratelimit())
    dev_warn(...);
}

HTH, Torsten