From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mms2.broadcom.com ([216.31.210.18]:3087 "EHLO mms2.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752075Ab2GHTlY (ORCPT ); Sun, 8 Jul 2012 15:41:24 -0400 Message-ID: <4FF9E254.7090203@broadcom.com> (sfid-20120708_214128_611626_6B7E61CD) Date: Sun, 8 Jul 2012 21:41:08 +0200 From: "Arend van Spriel" MIME-Version: 1.0 To: "John W. Linville" cc: thomas , "Johannes Berg" , linux-wireless@vger.kernel.org, nbd@openwrt.org, brcm80211-dev-list@broadcom.com, pieterpg@broadcom.com, gregkh@suse.de, frankyl@broadcom.com, rvossen@broadcom.com, brudley@broadcom.com Subject: Re: [PATCH v2] brcmsmac: restructure info->control.sta handling as it is goning to be removed soon. References: <1340974563-77085-1-git-send-email-thomas@net.t-labs.tu-berlin.de> <1340975210.4472.1.camel@jlt3.sipsolutions.net> <4FEDC3F0.1000201@net.t-labs.tu-berlin.de> <20120706193733.GC1879@tuxdriver.com> In-Reply-To: <20120706193733.GC1879@tuxdriver.com> Content-Type: text/plain; charset=iso-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 07/06/2012 09:37 PM, John W. Linville wrote: > On Fri, Jun 29, 2012 at 11:04:16AM -0400, thomas wrote: >> Johannes Berg schrieb: >> >>> On Fri, 2012-06-29 at 05:56 -0700, Thomas Huehn wrote: >>>> brcmsmac uses info->control.sta while doing ampdu aggregation. This patch >>>> changes the usage of the structure info->control.sta, as it is going to be >>>> removed soon from struct ieee80211_tx_info. This patch is a pre-requisit in >>>> order to add transmission power control (TPC) to the mac80211 subsystem. >>>> >>>> Suggested-by: Felix Fietkau >>>> Signed-off-by: Thomas Huehn >>>> --- >>>> Change sequence of overwriting data. Thx to Johannes. >>> >>> >>>> @@ -665,7 +665,7 @@ brcms_c_sendampdu(struct ampdu_info *ampdu, struct brcms_txq_info *qi, >>>> u8 plcp0, plcp3, is40, sgi; >>>> struct ieee80211_sta *sta; >>>> >>>> - sta = tx_info->control.sta; >>>> + sta = tx_info->rate_driver_data[0]; >>> >>> Are you sure it actually works now? >> >> >> From locking at the code, sta is never used after it gets overridden. >> The brcmsmac driver does not use the vif pointer at all. I asked Felix >> to double check as I do not have a Broadcom device over here. >> >> Bye Thomas > > Any comments on this one from the Broadcom camp? > Hi John, Just applied the patch to have a closer look at the changes, but I am missing details on the whole story. I see tx_info->rate_driver_data[0] being set in the tx callback and reset to NULL in some other path which I believe is only called upon tid or sta removal so it does not make sense to me. I have pushed the patch to our internal review server as I would like some co-workers to have a look. If anyone can provide any more details what this patch is trying to solve, please do. Gr. AvS