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Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1p49cy-00Auet-2n; Sat, 10 Dec 2022 23:51:32 +0000 Date: Sat, 10 Dec 2022 23:51:32 +0000 From: Al Viro To: Nhat Pham Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, bfoster@redhat.com, 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: <20221205175140.1543229-4-nphamcs@gmail.com> X-Rspamd-Queue-Id: A976D40003 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: o4mrcr1opph86az3umktu3b4837m1aic X-HE-Tag: 1670716297-355740 X-HE-Meta: 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 W/L7IRzS shKujivVZIAp2Ukik3jO8+SmI8MbcyKb2Oij3RWzumOXmoEVUueaJf+UZU+lgnLXL1+dXfs3pzElNozK8WPWfygyNCA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.002384, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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.