From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: changing dev->needed_headroom/needed_tailroom? Date: Fri, 2 Aug 2013 10:55:58 +0200 Message-ID: <1375433758.24371.20.camel@deadeye.wl.decadent.org.uk> References: <1374850210.8248.59.camel@jlt4.sipsolutions.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: , To: Johannes Berg Return-path: In-Reply-To: <1374850210.8248.59.camel-8Nb76shvtaUJvtFkdXX2HixXY32XiHfO@public.gmane.org> Sender: linux-wireless-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Fri, 2013-07-26 at 16:50 +0200, Johannes Berg wrote: > Does it seem reasonable to change dev->needed_headroom and > dev->needed_tailroom on the fly? > > We currently set needed_headroom to the max of what we need, but we > could do better like making it depend on the interface type (e.g. only > asking for mesh space on mesh interfaces). This would be done only when > the interface isn't connected, I can't promise it would be down but the > carrier would be off. [...] I don't think this is safe when the interface is running (even if carrier is off). Some functions may read dev->needed_headroom twice and rely on getting the same value each time. Also, stacked devices would need to adjust their own needed_headroom accordingly. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html