From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH 08/13] net: convert drivers to paged frag API. Date: Fri, 22 Jul 2011 15:16:04 +0100 Message-ID: <1311344164.12772.78.camel@zakaz.uk.xensource.com> References: <1311340095.12772.57.camel@zakaz.uk.xensource.com> <1311340653-19336-8-git-send-email-ian.campbell@citrix.com> <20110722.071217.607687554920673786.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Chas Williams , To: David Miller Return-path: In-Reply-To: <20110722.071217.607687554920673786.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Fri, 2011-07-22 at 15:12 +0100, David Miller wrote: > From: Ian Campbell > Date: Fri, 22 Jul 2011 14:17:28 +0100 > > > - put_dma(tx->index,eni_dev->dma,&j,(unsigned long) > > - skb_shinfo(skb)->frags[i].page + skb_shinfo(skb)->frags[i].page_offset, > > + put_dma(tx->index,eni_dev->dma,&j, > > + (unsigned long)skb_frag_address(&skb_shinfo(skb)->frags[i]), > > This is not an equivalent transformation. > > skb_frag_address() does a page_address() on the frag page, but that is > not what the code was doing here previously. > > It's possible the code was buggy, but you can't do a fix like that > amidst what is supposed to be a semantically NOP transformation. Ouch, you are absolutely right, I didn't spot that, sorry. The original code does look pretty bogus though, indexing off a struct page * like that -- CC'ing the ATM maintainer + list. Ian. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html