From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ajit Khaparde Subject: Re: [RFC PATCH 00/10] Remove skb_dma_map/unmap calls Date: Wed, 25 Nov 2009 17:00:51 +0530 Message-ID: <20091125113050.GA19837@serverengines.com> References: <20091125011111.32704.3009.stgit@gitlad.jf.intel.com> Reply-To: Ajit Khaparde Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: mcarlson@broadcom.com, mchan@broadcom.com, sathyap@serverengines.com, subbus@serverengines.com, davem@davemloft.net, netdev@vger.kernel.org To: Alexander Duyck Return-path: Received: from mail-px0-f180.google.com ([209.85.216.180]:63512 "EHLO mail-px0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752454AbZKYLan (ORCPT ); Wed, 25 Nov 2009 06:30:43 -0500 Received: by pxi10 with SMTP id 10so5682028pxi.33 for ; Wed, 25 Nov 2009 03:30:49 -0800 (PST) Content-Disposition: inline In-Reply-To: <20091125011111.32704.3009.stgit@gitlad.jf.intel.com> Sender: netdev-owner@vger.kernel.org List-ID: On 24/11/09 17:20 -0800, Alexander Duyck wrote: > This patch series removes the skb_dma_map and skb_dma_unmap function calls. > The reason for this change is because the use of skb_dma_map/unmap can lead > to serious issues when HW IOMMU is enabled. This is because each mapping > of the skb with a HW IOMMU enabled results in a new set of DMA mappings. > This in turn leads to issues when skbs are cloned for uses such as > bridging or pktgen because each transmitting device will update the skb > shared info structure resulting in some mappings being overwritten, and others > being freed multiple times. If this is the case can the members related to the dma mapping stuff (skb_shinfo(skb)->dma_maps) be moved out of this shared info structure and we retain this "good" abstraction provided by this skb_dma_map/unmap api? > > I am looking for input specifically on the tg3, be2net, and bnx2 driver > patches as I am not very familiar with them and I am not certain if > additional changes are required. > be2net: remove use of skb_dma_map/unmap > > drivers/net/benet/be_main.c | 37 ++++++--- We have pulled the be2net specific patch for testing and review. We will send an update once done with it. -Ajit