Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:36748 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753853Ab0EKSPM (ORCPT ); Tue, 11 May 2010 14:15:12 -0400 Date: Tue, 11 May 2010 14:14:39 -0400 From: "John W. Linville" To: Abhijeet Kolekar Cc: linux-wireless@vger.kernel.org, yi.zhu@intel.com Subject: Re: [PATCH V3] mac80211: fix paged defragmentation Message-ID: <20100511181439.GB2400@tuxdriver.com> References: <1273602131-9188-1-git-send-email-abhijeet.kolekar@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1273602131-9188-1-git-send-email-abhijeet.kolekar@intel.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, May 11, 2010 at 11:22:11AM -0700, Abhijeet Kolekar wrote: > Paged RX skb patch broke the defragmentation. We need to read hdr again > after linearization. > > It fixes following bug > http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=2194 > > Signed-off-by: Zhu, Yi > Signed-off-by: Abhijeet Kolekar > --- > v2: Changed hdr reading. > v3: Added more comments. > net/mac80211/rx.c | 6 ++++++ > 1 files changed, 6 insertions(+), 0 deletions(-) > > diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c > index 9a08f2c..6e2a7bc 100644 > --- a/net/mac80211/rx.c > +++ b/net/mac80211/rx.c > @@ -1253,6 +1253,12 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) > if (skb_linearize(rx->skb)) > return RX_DROP_UNUSABLE; > > + /* > + * skb_linearize() might change the skb->data and > + * previously cached variables (in this case, hdr) need to > + * be refreshed with the new data. > + */ > + hdr = (struct ieee80211_hdr *)rx->skb->data; > seq = (sc & IEEE80211_SCTL_SEQ) >> 4; > > if (frag == 0) { And what about making sure the compiler doesn't optimize this away? John -- John W. Linville Someday the world will need a hero, and you linville@tuxdriver.com might be all we have. Be ready.