From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B9CB9446A1; Fri, 10 May 2024 17:29:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715362169; cv=none; b=cGohw4gb0+zb6Ob66QZS4vOSFiKm0fwNhjJKnnB6bmt4UZHyeQlkBXnEUtZzW6EqQ6AjJDoyLPnT5OFbCCw82ApVF7WFkTapK+HMi8Mwj803P/uTyjfsfX1WqKchjO6OOfxNd1lQuRJwr3BQ6AqwunyNW3FKUVObRkW2RS5GbIs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715362169; c=relaxed/simple; bh=9FerCyrlgXwGRxoi932MXaGZORA1hI35HAt1Vop6+YQ=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=qoiDqSzGbWhqiLo4xLIJfoNex57MqrX2jWokMVzGcz8p5am6DI4dPGXpkq7xkj0I0NSxIavV9F1HQTec4Y62qYCIfLJDQ1lqwi+1gSXxjDCUjAOdJzbWlEQ89Qi5d65mol42J7FEw2BTiBA0g77bAW6BdIjZGUwaIZB7BUlXxPo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sx36sAne; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sx36sAne" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B3BDC113CC; Fri, 10 May 2024 17:29:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715362169; bh=9FerCyrlgXwGRxoi932MXaGZORA1hI35HAt1Vop6+YQ=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=sx36sAne/FEdqP1wxc3/9KU/1ADr2ABOKYQiWOPcLEPs7AGhMXqK2tolxinjZNh8g V+Aj73S9RmD2emupDMTeozc6bu7seT5B4P3CRwJI/G97mWUXJ3sCOtK2msyiOBJtoP tYqOQjIGhObhfVjIUud6IF4PX9G6lH47RcVp14dIPryQY957LfXOvTFuT3yhUxCd1B Ho7P8ZEKjojtQQjfewVaUxSgnKaQirDN9Yxi1fTcGUuA6vvL+f1k0PVSm+o3QzGdss yDht4MhsNnH6EhmNm0ZDiJLKFSmsEelXnsOJWLp5OfS61/YUTSsWJm0W+TvqfYmLx8 35N0rxk3yjgkg== Date: Fri, 10 May 2024 10:29:28 -0700 (PDT) From: Mat Martineau To: Yunsheng Lin cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Duyck , Ayush Sawal , Eric Dumazet , Willem de Bruijn , Jason Wang , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , John Fastabend , Jakub Sitnicki , David Ahern , Matthieu Baerts , Geliang Tang , Jamal Hadi Salim , Cong Wang , Jiri Pirko , Boris Pismenny , bpf@vger.kernel.org, mptcp@lists.linux.dev Subject: Re: [PATCH net-next v3 11/13] net: replace page_frag with page_frag_cache In-Reply-To: Message-ID: <9a3cea15-2001-2222-0d0d-5f61f90507c3@kernel.org> References: <20240508133408.54708-1-linyunsheng@huawei.com> <20240508133408.54708-12-linyunsheng@huawei.com> <334a8c67-87c8-a918-9517-0afbfae0d02b@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed On Fri, 10 May 2024, Yunsheng Lin wrote: > On 2024/5/10 0:22, Mat Martineau wrote: >> On Wed, 8 May 2024, Yunsheng Lin wrote: >> >>> Use the newly introduced prepare/probe/commit API to >>> replace page_frag with page_frag_cache for sk_page_frag(). >>> >>> CC: Alexander Duyck >>> Signed-off-by: Yunsheng Lin >>> --- >>> .../chelsio/inline_crypto/chtls/chtls.h | 3 - >>> .../chelsio/inline_crypto/chtls/chtls_io.c | 100 ++++--------- >>> .../chelsio/inline_crypto/chtls/chtls_main.c | 3 - >>> drivers/net/tun.c | 28 ++-- >>> include/linux/sched.h | 4 +- >>> include/net/sock.h | 14 +- >>> kernel/exit.c | 3 +- >>> kernel/fork.c | 3 +- >>> net/core/skbuff.c | 32 ++-- >>> net/core/skmsg.c | 22 +-- >>> net/core/sock.c | 46 ++++-- >>> net/ipv4/ip_output.c | 33 +++-- >>> net/ipv4/tcp.c | 35 ++--- >>> net/ipv4/tcp_output.c | 28 ++-- >>> net/ipv6/ip6_output.c | 33 +++-- >>> net/kcm/kcmsock.c | 30 ++-- >>> net/mptcp/protocol.c | 70 +++++---- >>> net/sched/em_meta.c | 2 +- >>> net/tls/tls_device.c | 139 ++++++++++-------- >>> 19 files changed, 331 insertions(+), 297 deletions(-) >>> >> >> >> >>> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c >>> index bb8f96f2b86f..ab844011d442 100644 >>> --- a/net/mptcp/protocol.c >>> +++ b/net/mptcp/protocol.c >>> @@ -960,17 +960,18 @@ static bool mptcp_skb_can_collapse_to(u64 write_seq, >>> } >>> >>> /* we can append data to the given data frag if: >>> - * - there is space available in the backing page_frag >>> - * - the data frag tail matches the current page_frag free offset >>> + * - there is space available for the current page >>> + * - the data frag tail matches the current page and offset >>> * - the data frag end sequence number matches the current write seq >>> */ >>> static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, >>> - const struct page_frag *pfrag, >>> + const struct page *page, >>> + const unsigned int offset, >>> + const unsigned int size, >> >> Hi Yunsheng - >> >> Why add the 'size' parameter here? It's checked to be a nonzero value, >> but it can only be 0 if page is also NULL. In this case "page == >> df->page" will be false, so the function will return false even without >> checking 'size'. > > Is it possible that the pfrag->page is also NULL, which may cause > mptcp_frag_can_collapse_to() to return true? Not sure. But I do know that df->page will never be NULL, so "page == df->page" will always be false when page == NULL. > > I just found out that the 'size' is not set to zero when return > NULL for the implementation of probe API for the current version. > Perhaps it makes more sense to expect the API caller to make sure > the the returned 'page' not being NULL before using the 'offset', > 'size' and 'va', like below: > > df && page && page == df->page > Given that df->page is never NULL, I don't think the extra "&& page" is needed. - Mat