Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934632AbYCFOVV (ORCPT ); Thu, 6 Mar 2008 09:21:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764317AbYCFOVA (ORCPT ); Thu, 6 Mar 2008 09:21:00 -0500 Received: from courier.cs.helsinki.fi ([128.214.9.1]:58086 "EHLO mail.cs.helsinki.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762470AbYCFOU7 (ORCPT ); Thu, 6 Mar 2008 09:20:59 -0500 Date: Thu, 6 Mar 2008 16:20:57 +0200 (EET) From: Pekka J Enberg To: Patrick McHardy cc: Netfilter Development Mailinglist , clameter@sgi.com, joe@perches.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Netfilter Development Mailinglist Subject: Re: [PATCH] netfilter: replace horrible hack with ksize() In-Reply-To: Message-ID: References: <47CFF9B7.5060803@trash.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1177 Lines: 32 On Thu, 6 Mar 2008, Pekka J Enberg wrote: > > > - if (newlen >= ct->ext->real_len) { > > > + if (newlen >= ksize(ct->ext)) { > > > > This needs to look at the currently allocated size, otherwise > > it will always realloc when adding new extensions after having > > used up ksize(ct->ext) space. > > Lets say you > > p = kmalloc(8, ...); > > Then ksize(p) will return the currently allocated size which is 32 bytes > when page size is 4 KB, and not 8 bytes. So it should be equivalent of > what the current code does. > > What am I missing here? Ok, it's not equivalent. We have two sizes: object size (8 bytes) and buffer size (32 bytes) here. In netfilter, ->real_len is same as object size, not buffer size as ksize() is. But now I am officially even more confused, why does the netfilter code decided whether to reallocate based on _object size_ and not _buffer size_ (as krealloc() does, for example)? Pekka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/