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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44C19C4332F for ; Mon, 12 Dec 2022 16:24:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D4EC78E0003; Mon, 12 Dec 2022 11:24:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CFE8C8E0002; Mon, 12 Dec 2022 11:24:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BECDF8E0003; Mon, 12 Dec 2022 11:24:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id B10838E0002 for ; Mon, 12 Dec 2022 11:24:58 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 7B107140765 for ; Mon, 12 Dec 2022 16:24:58 +0000 (UTC) X-FDA: 80234178276.05.052B3AC Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf17.hostedemail.com (Postfix) with ESMTP id DA9F14001E for ; Mon, 12 Dec 2022 16:24:54 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=JSx+G5IE; spf=none (imf17.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1670862297; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=qTolJC9fUfjb3pLzxYSP1dBl1foIc1xzVjzAvOAu5Oo=; b=xlrHHdaIqArOvIlZ6u79UptX8ltsJwi/mf9EycRRpiWuQAXjl3DlsBk0ZPPtkhdkv5HJvr I5mhDAPcfTtDEBcNwohhCcz9qYPqKefOaAPl0sPq9BlYeTvYoWtGhGIDZUZEjPNLrCp7U0 Irnu0y8F20SMRl9BqQzYTmZAFv28k6o= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=JSx+G5IE; spf=none (imf17.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1670862297; a=rsa-sha256; cv=none; b=4Lb4wyukfL1hmfB7tHt/A0gJNCDO9JvcnpIQC8a1iw792+xEkvKyuVonl9VAT4ko8/4U3O IT+QWnsvY3KA1Uqv1zDRGS689R5pfBvSzU8LJpFB3vbpoonbSAMk+73onlfTyl62s5iZpg Zmuq/5TCzzP6LZh1hB3a1Ggy1ukpiSM= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=qTolJC9fUfjb3pLzxYSP1dBl1foIc1xzVjzAvOAu5Oo=; b=JSx+G5IEaMaHeabCqfyh2vEwKw ftLHw1tCdPxx6RJ4qQV6TEF4qayiik5lnF6rEEpqn0a/P1pZxhwY9vMfbQeulKM8uMX+t18wQiHGM Up77a2zYD1uXpqPunkKfpAVVpJXwDnq78QDQ499ll72LH3e2vdCVkwnhC4+hoYFNY0Ep5hKZ+oulA kN9DvK3uZPuMpmw5NjY8RMAS/COPov7o3mXCsgOViWg3YfF8Ke5dk3QPw6z8ucouVALOv2YfmGibo ULC4uNegvbFzfozPTb4cbtJkFYrRuNDESPg6wkqfOOS6t6/2pS40uDU2O/YJmjyxFixbl2UscW9+f SOH0T6fw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1p4lbu-00BDpp-Sf; Mon, 12 Dec 2022 16:24:58 +0000 Date: Mon, 12 Dec 2022 16:24:58 +0000 From: Matthew Wilcox To: Nhat Pham Cc: Al Viro , akpm@linux-foundation.org, hannes@cmpxchg.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, bfoster@redhat.com, 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: X-Stat-Signature: atp5477fjewqqadbn39jeyrhetkezihu X-Rspam-User: X-Rspamd-Queue-Id: DA9F14001E X-Rspamd-Server: rspam06 X-HE-Tag: 1670862294-130360 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Dec 12, 2022 at 08:23:31AM -0800, Nhat Pham wrote: > > It would be easier to read if you inverted the condition here. > > Oh I think I tried > > if (!f.file) > return -EBADF; > > here, but there are some mixing-code-with-decl warnings. > If I recall correctly, the problem is with this line: > > XA_STATE(xas, &mapping->i_pages, first_index); > > which is expanded into a declaration: > > #define XA_STATE(name, array, index) \ > struct xa_state name = __XA_STATE(array, index, 0, 0) > > It requires a valid mapping though, which is > obtained from f.file: > > struct address_space *mapping = f.file->f_mapping; > > so it cannot be moved above the if(!f.file) check either... Perhaps you're trying to do too much in a single function?