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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 16515C433E2 for ; Tue, 19 May 2020 16:14:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D4C892075F for ; Tue, 19 May 2020 16:14:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4C892075F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6999F900003; Tue, 19 May 2020 12:14:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 62275900002; Tue, 19 May 2020 12:14:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 510DE900003; Tue, 19 May 2020 12:14:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0039.hostedemail.com [216.40.44.39]) by kanga.kvack.org (Postfix) with ESMTP id 36C80900002 for ; Tue, 19 May 2020 12:14:23 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id E684C8248076 for ; Tue, 19 May 2020 16:14:22 +0000 (UTC) X-FDA: 76833965964.12.dirt00_7d804c85f5e21 X-HE-Tag: dirt00_7d804c85f5e21 X-Filterd-Recvd-Size: 2192 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Tue, 19 May 2020 16:14:22 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 1F99968B02; Tue, 19 May 2020 18:14:19 +0200 (CEST) Date: Tue, 19 May 2020 18:14:18 +0200 From: Christoph Hellwig To: Linus Torvalds Cc: Christoph Hellwig , the arch/x86 maintainers , Alexei Starovoitov , Daniel Borkmann , Masami Hiramatsu , Andrew Morton , linux-parisc@vger.kernel.org, linux-um , Netdev , bpf@vger.kernel.org, Linux-MM , Linux Kernel Mailing List Subject: Re: [PATCH 11/20] bpf: factor out a bpf_trace_copy_string helper Message-ID: <20200519161418.GA26545@lst.de> References: <20200519134449.1466624-1-hch@lst.de> <20200519134449.1466624-12-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) 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 Tue, May 19, 2020 at 09:07:55AM -0700, Linus Torvalds wrote: > On Tue, May 19, 2020 at 6:45 AM Christoph Hellwig wrote: > > > > + switch (fmt_ptype) { > > + case 's': > > +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE > > + strncpy_from_unsafe(buf, unsafe_ptr, bufsz); > > + break; > > +#endif > > + case 'k': > > + strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz); > > + break; > > That 's' case needs a "fallthrough;" for the overlapping case, > methinks. Otherwise you'll get warnings. I don't think we need it as the case of case 'a': case 'b': do_stuff(); break; has always been fine even with the fallthough warnings. And the rest of the stuff gets removed by cpp..