From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: [PATCH] TX_RING and packet mmap Date: Sun, 12 Apr 2009 14:32:12 +0400 Message-ID: <20090412103212.GA28397@ioremap.net> References: <1238701718.5669.26.camel@bender> <20090407072647.GA11480@gondor.apana.org.au> <1239108520.32737.28.camel@dogo.mojatatu.com> <20090407130447.GA14329@gondor.apana.org.au> <1239112067.32737.51.camel@dogo.mojatatu.com> <7e0dd21a0904070738jd8a2714wd840352699f1e9f1@mail.gmail.com> <1239137800.21227.10.camel@dogo.mojatatu.com> <20090407211130.GA5918@ioremap.net> <7e0dd21a0904081406w31da460pe1c0c7153538f283@mail.gmail.com> <7e0dd21a0904120327q537956abkf75a17d477cc2e61@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Herbert Xu , netdev@vger.kernel.org, "David S. Miller" , Patrick McHardy , jamal To: Johann Baudy Return-path: Received: from cet.com.ru ([195.178.208.66]:50529 "EHLO tservice.net.ru" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755241AbZDLKcO (ORCPT ); Sun, 12 Apr 2009 06:32:14 -0400 Content-Disposition: inline In-Reply-To: <7e0dd21a0904120327q537956abkf75a17d477cc2e61@mail.gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: Hi Johann. Sorry for long reply. On Sun, Apr 12, 2009 at 12:27:04PM +0200, Johann Baudy (johann.baudy@gnu-log.net) wrote: > Do you mean that skb_shinfo(skb)->frags[i].page will be valid until > destructor? even if linearized, cloned ....? Page itself will live until destruction time, when skb is linearized page is freed, so your own destructor will find that given page is no longer used, and appropriate memory area can be overwritten. When skb is cloned, page is untouched, only shared info reference counter is increased. -- Evgeniy Polyakov