lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-Id: <20100125.154814.56026460.davem@davemloft.net> Date: Mon, 25 Jan 2010 15:48:14 -0800 (PST) From: David Miller <davem@...emloft.net> To: shemminger@...tta.com Cc: netdev@...r.kernel.org Subject: Re: [PATCH] tcp_probe: avoid modulus operation and wrap fix From: Stephen Hemminger <shemminger@...tta.com> Date: Mon, 25 Jan 2010 08:30:06 -0800 > On Sun, 24 Jan 2010 22:41:22 -0800 (PST) > David Miller <davem@...emloft.net> wrote: > >> From: Stephen Hemminger <shemminger@...tta.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? > > Yes. in this ring; empty is head == tail, and full needs to > be tail == head - 1. Ok, that makes sense, thanks for explaining. Applied, thanks Stephen. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists