From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from s3.sipsolutions.net ([5.9.151.49]:51792 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753635AbbCBSxr (ORCPT ); Mon, 2 Mar 2015 13:53:47 -0500 Message-ID: <1425322425.1906.4.camel@sipsolutions.net> (sfid-20150302_195354_759126_A9E6657C) Subject: Re: [PATCH RFC 08/14] net: wireless: mac80211: shrink ieee80211_tx_info From: Johannes Berg To: Florian Westphal Cc: netdev@vger.kernel.org, linux-wireless@vger.kernel.org Date: Mon, 02 Mar 2015 19:53:45 +0100 In-Reply-To: <1425318028-26531-9-git-send-email-fw@strlen.de> (sfid-20150302_184059_463522_70F2B3E8) References: <1425318028-26531-1-git-send-email-fw@strlen.de> <1425318028-26531-9-git-send-email-fw@strlen.de> (sfid-20150302_184059_463522_70F2B3E8) Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Mon, 2015-03-02 at 18:40 +0100, Florian Westphal wrote: > to make it fit into (future) 44-byte sized skb->cb[]. > > This works, since flags is only used to store values > from mac80211_tx_control_flags enum, and these are just 2 bits. > We can thus move this to the padding hole inside the union. > > Also add BUILD_BUG_ON magic to make sure that the new flags > field doesn't share storage w. other members of the union. This is really ugly - what's the point of this? Mind you - we are actually acutely out of space and would rather have *more*, not less. johannes