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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1FF2C4332F for ; Mon, 12 Dec 2022 13:23:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232623AbiLLNXg (ORCPT ); Mon, 12 Dec 2022 08:23:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232602AbiLLNXQ (ORCPT ); Mon, 12 Dec 2022 08:23:16 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E90BFEE for ; Mon, 12 Dec 2022 05:22:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670851343; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=lHbD0bc62wnvFcvyZgL/qUAul189e+x07WK3pUf5sj4=; b=ibjgvxTXoiBV4f5vhmpQwqKT545cZVovJpS8d7uzhIPm0OXDd+TcSBLVH47oGZcBSDE+ib nvNcxmE+gcqmR7GwyCbKIM66VT7wu5WrIpvlw2TieKWC/ZTinKCw314D8PKmvgL2+wOkR/ o1rez4/FJFq6sksNSCdn33FYQso9m8M= Received: from mail-qv1-f69.google.com (mail-qv1-f69.google.com [209.85.219.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-581-zyDuQbhfNQWjz-MR1cTcPA-1; Mon, 12 Dec 2022 08:22:22 -0500 X-MC-Unique: zyDuQbhfNQWjz-MR1cTcPA-1 Received: by mail-qv1-f69.google.com with SMTP id y11-20020ad457cb000000b004c6fafdde42so11569830qvx.5 for ; Mon, 12 Dec 2022 05:22:22 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=lHbD0bc62wnvFcvyZgL/qUAul189e+x07WK3pUf5sj4=; b=KoAqHR4UriHXB2YqifWa6j0Xl9q2CCamFBFn+sh7OkeojPpUBP733/Oe41pfvou9FS BiM68Y6zTCMQfjc3KPA2DLHdOde2qMjCDhT8Qr52J42SI5DMW0Vob9geRn0gK10Zd8iS 4zFZV4FfvYM+9tXhs8buu+nEfr9SbcvGH/nRO0dILZOQqKVLeaJFerBxOayfxAGtgMPJ H9yZfTzvhlOjUoPufJrWvHmeGVIeQmavqzbxZLaEyLcQDkmIcR3dVCpCzotPg2sE9lEw 3sdQNIE/d0X+IpVe6c3R2cBFys3J/bc/UTd9iA/8aNPotVpenuGR4mtVhgdzoKEQqMLF RG7g== X-Gm-Message-State: ANoB5pl7PdeEhXnYtHItmtAvWmzbRHW1QucPQiwtNitJ728o520VqugW zudaWXcwwW3aS1zW2mf3GZIQ+cqx1rqz8as2eeJWZZSD6L1chVdHpXoohH2+krzVTt1uXyHNhIR oYQ1vH38+zVOgIiuq4wXXdx6x X-Received: by 2002:a05:622a:18a1:b0:3a7:f669:4599 with SMTP id v33-20020a05622a18a100b003a7f6694599mr33800684qtc.62.1670851341721; Mon, 12 Dec 2022 05:22:21 -0800 (PST) X-Google-Smtp-Source: AA0mqf7Dsnp4gnwGIrvBBlo7rjiD+yh/h1xU3xuWVWjf9K0mQgn/zO86Bt1+cxSVx+kIzoAr5tnnMQ== X-Received: by 2002:a05:622a:18a1:b0:3a7:f669:4599 with SMTP id v33-20020a05622a18a100b003a7f6694599mr33800646qtc.62.1670851341442; Mon, 12 Dec 2022 05:22:21 -0800 (PST) Received: from bfoster (c-24-61-119-116.hsd1.ma.comcast.net. [24.61.119.116]) by smtp.gmail.com with ESMTPSA id h18-20020ac846d2000000b003a55fe9f352sm5713126qto.64.2022.12.12.05.22.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Dec 2022 05:22:20 -0800 (PST) Date: Mon, 12 Dec 2022 08:22:26 -0500 From: Brian Foster To: Al Viro Cc: Nhat Pham , akpm@linux-foundation.org, hannes@cmpxchg.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, willy@infradead.org, kernel-team@meta.com Subject: Re: [PATCH v2 3/4] cachestat: implement cachestat syscall Message-ID: References: <20221205175140.1543229-1-nphamcs@gmail.com> <20221205175140.1543229-4-nphamcs@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Dec 10, 2022 at 11:51:32PM +0000, Al Viro wrote: > On Mon, Dec 05, 2022 at 09:51:39AM -0800, Nhat Pham wrote: > > > + if (!access_ok(cstat, sizeof(struct cachestat))) > > + return -EFAULT; > > What for? You are using copy_to_user() later, right? > > > + f = fdget(fd); > > + if (f.file) { > > It would be easier to read if you inverted the condition here. > Seconded.. I mentioned the same the last time I looked at this. On looking again, perhaps it might even make sense to create a filemap_cachestat() to split up the syscall bits from the associated map walking bits..? That subsequently raises the question of whether a new .c file is really necessary.. Brian