linux-kernel - Re: [RFC PATCH] consolidate within() implementations

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <18501.2572.137148.78927@harpo.it.uu.se>
Date:	Tue, 3 Jun 2008 11:08:28 +0200
From:	Mikael Pettersson <mikpe@...uu.se>
To:	Peter Oberparleiter <peter.oberparleiter@...ibm.com>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Harvey Harrison <harvey.harrison@...il.com>,
	Peter Oberparleiter <oberparleiter@...glemail.com>
Subject: Re: [RFC PATCH] consolidate within() implementations

Peter Oberparleiter writes:
 > +static inline int addr_within_len(const void *addr, const void *start,
 > +				  size_t len)
 > +{
 > +	return ((unsigned long) addr >= (unsigned long) start) &&
 > +	       ((unsigned long) addr < ((unsigned long) start + len));
 > +}

On most machines you'd get better code with

	return (unsigned long)((char*)addr - (char*)start) < (unsigned long)len;

Maybe a candidate for a follow-up optimisation patch?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/