From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sat, 16 Apr 2022 19:26:59 +0200 From: Andrew Lunn Subject: Re: [PATCH] batman-adv: Don't skb_split skbuffs with frag_list Message-ID: References: <20220416122434.33061-1-sven@narfation.org> <2248548.8ZbxvZVH5L@sven-l14> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2248548.8ZbxvZVH5L@sven-l14> List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Sven Eckelmann Cc: The list for a Better Approach To Mobile Ad-hoc Networking , Felix Kaechele On Sat, Apr 16, 2022 at 07:17:28PM +0200, Sven Eckelmann wrote: > On Saturday, 16 April 2022 16:21:19 CEST Andrew Lunn wrote: > > This is not an area of the kernel i'm very familiar with. But i'm > > wondering, is this a BATMAN specific problem, or a generic problem? > > Should the fix be in BATMAN, or the core? > > I understand what you mean. But let me cite two places which required to > operate on parts of the frag lists: > > /* If we need update frag list, we are in troubles. > * Certainly, it is possible to add an offset to skb data, > * but taking into account that pulling is expected to > * be very rare operation, it is worth to fight against > * further bloating skb head and crucify ourselves here instead. > * Pure masohism, indeed. 8)8) > */ > > /* Misery. We are in troubles, going to mincer fragments... */ > > > And since I cannot reproduce this here at the moment, I've decided not to > start with that. O.K. The BUG_ON() should at least catch other drivers hitting the same issue, and hopefully a search engine will point to this discussion. However, i suggest you post the fix to netdev, and see what others think. Andrew