From: David Miller <davem@davemloft.net>
To: shemminger@vyatta.com
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH] tcp_probe: avoid modulus operation and wrap fix
Date: Sun, 24 Jan 2010 22:41:22 -0800 (PST) [thread overview]
Message-ID: <20100124.224122.13742906.davem@davemloft.net> (raw)
In-Reply-To: <20100124215001.78251e25@nehalam>
From: Stephen Hemminger <shemminger@vyatta.com>
Date: Sun, 24 Jan 2010 21:50:01 -0800
> @@ -75,12 +75,12 @@ static struct {
>
> static inline int tcp_probe_used(void)
> {
> - return (tcp_probe.head - tcp_probe.tail) % bufsize;
> + return (tcp_probe.head - tcp_probe.tail) & (bufsize - 1);
> }
>
> static inline int tcp_probe_avail(void)
> {
> - return bufsize - tcp_probe_used();
> + return bufsize - tcp_probe_used() - 1;
> }
>
> /*
Hmmm... When the ring is full head==tail, which means
tcp_probe_used() returns 0. Which would now make tcp_probe_avail()
return "bufsize - 0 - 1".
Is that right?
next prev parent reply other threads:[~2010-01-25 6:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-25 5:50 [PATCH] tcp_probe: avoid modulus operation and wrap fix Stephen Hemminger
2010-01-25 6:41 ` David Miller [this message]
2010-01-25 16:30 ` Stephen Hemminger
2010-01-25 23:48 ` David Miller
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