From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B70CC4338F for ; Fri, 30 Jul 2021 12:16:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D64F861059 for ; Fri, 30 Jul 2021 12:16:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238623AbhG3MQt (ORCPT ); Fri, 30 Jul 2021 08:16:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:48460 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230350AbhG3MQt (ORCPT ); Fri, 30 Jul 2021 08:16:49 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 13D8361057; Fri, 30 Jul 2021 12:16:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627647404; bh=pTMZZqemx+Fyjde1qOP0j/hlEPsMgoeVfnOx61G/VbU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=d6DFxDhZ3UyrtglKUDq1+KvfXECMqI0NZ0vRISO3fH7EeQXdEdDyj5JY/yoTXhxjX GxZXXu5wSYBq9BegfKnvtrtVkdIuTOa+TTPFCNkoHs1H1mTMiNsWhgzxHyOrEn7YNE sQJJWKXqgnucGVeBsRkMyMHtse49JYLkO2oSMwldPRvERmPoDmT8cjNatp+R0xcQW8 d2nxYgu+sy1zn3xIGyE9uMUH3e4xBeHZyaPwxPfe71V7MN7nxSL7Iu101NFnWj7hXG CUv8WREPDbuqRLyJ4krQWfu18/KLEf4Wx4qcpFcgF2/XJ0/+NP9snMpb6A1BIplrNT S/96kUvSr8ACg== Date: Fri, 30 Jul 2021 05:16:43 -0700 From: Jakub Kicinski To: "Michael S. Tsirkin" , Xuan Zhuo , Jason Wang Cc: netdev@vger.kernel.org, "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , virtualization@lists.linux-foundation.org, bpf@vger.kernel.org Subject: Re: [PATCH net v2 0/2] virtio-net: fix for build_skb() Message-ID: <20210730051643.54198a9e@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210601070610-mutt-send-email-mst@kernel.org> References: <20210601064000.66909-1-xuanzhuo@linux.alibaba.com> <20210601070610-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, 1 Jun 2021 07:06:43 -0400 Michael S. Tsirkin wrote: > On Tue, Jun 01, 2021 at 02:39:58PM +0800, Xuan Zhuo wrote: > > #1 Fixed a serious error. > > #2 Fixed a logical error, but this error did not cause any serious consequences. > > > > The logic of this piece is really messy. Fortunately, my refactored patch can be > > completed with a small amount of testing. > > Looks good, thanks! > Also needed for stable I think. > > Acked-by: Michael S. Tsirkin Just a heads up folks, looks like we ended up merging both this and the net-next version of the patch set: 8fb7da9e9907 virtio_net: get build_skb() buf by data ptr 5c37711d9f27 virtio-net: fix for unable to handle page fault for address and 7bf64460e3b2 virtio-net: get build_skb() buf by data ptr 6c66c147b9a4 virtio-net: fix for unable to handle page fault for address Are you okay with the code as is or should we commit something like: --- diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 56c3f8519093..74482a52f076 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -380,7 +380,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, struct page *page, unsigned int offset, unsigned int len, unsigned int truesize, bool hdr_valid, unsigned int metasize, - bool whole_page) + unsigned int headroom) { struct sk_buff *skb; struct virtio_net_hdr_mrg_rxbuf *hdr; @@ -398,28 +398,16 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, else hdr_padded_len = sizeof(struct padded_vnet_hdr); - /* If whole_page, there is an offset between the beginning of the + /* If headroom is not 0, there is an offset between the beginning of the * data and the allocated space, otherwise the data and the allocated * space are aligned. * * Buffers with headroom use PAGE_SIZE as alloc size, see * add_recvbuf_mergeable() + get_mergeable_buf_len() */ - if (whole_page) { - /* Buffers with whole_page use PAGE_SIZE as alloc size, - * see add_recvbuf_mergeable() + get_mergeable_buf_len() - */ - truesize = PAGE_SIZE; - - /* page maybe head page, so we should get the buf by p, not the - * page - */ - tailroom = truesize - len - offset_in_page(p); - buf = (char *)((unsigned long)p & PAGE_MASK); - } else { - tailroom = truesize - len; - buf = p; - } + truesize = headroom ? PAGE_SIZE : truesize; + tailroom = truesize - len - headroom; + buf = p - headroom; len -= hdr_len; offset += hdr_padded_len; @@ -978,7 +966,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, put_page(page); head_skb = page_to_skb(vi, rq, xdp_page, offset, len, PAGE_SIZE, false, - metasize, true); + metasize, + VIRTIO_XDP_HEADROOM); return head_skb; } break; @@ -1029,7 +1018,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, rcu_read_unlock(); head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog, - metasize, !!headroom); + metasize, headroom); curr_skb = head_skb; if (unlikely(!curr_skb))