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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 22F3CC433DB for ; Wed, 23 Dec 2020 15:53:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAFD722227 for ; Wed, 23 Dec 2020 15:53:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729073AbgLWPxi (ORCPT ); Wed, 23 Dec 2020 10:53:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727790AbgLWPxh (ORCPT ); Wed, 23 Dec 2020 10:53:37 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F32CC061794 for ; Wed, 23 Dec 2020 07:52:57 -0800 (PST) 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=ZzbHBDfwrLQXFpf8glXNdNep4b6to1I3c9fdVvbb1Rs=; b=LlAfVZ832CeCQX4WS/8e9Xf542 fq6syhLmhblRiPAq27ncYBnNMRz0gxp4abk3jaGqVkgM4tFkZ+h0MYyPbDT2xIZyukR0yGNKU+IJz iqUL3SFNRNALIzi1a3baXE7OfCEGizF9XiczWvjVWg9z91W0hndB5/9l/drrAJZ8dF3Oe6eNsevO1 bKxQaiy93pQ9Cg1QqSbkZhFpiWU95Dol283GyrEhxyFkw8bzmjL1+GeQqrE0KJKtoKayKXSQK21uR C4jbqUgqtAlX3ud0TFj6sAn7I6ZwWI48rlMJC1CxzJtv+6RMjPVqFFdHJcwnO8rrOThH+SN7Xk824 fz9Hftbg==; Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ks6Ra-0001f9-KX; Wed, 23 Dec 2020 15:52:54 +0000 Date: Wed, 23 Dec 2020 15:52:54 +0000 From: Christoph Hellwig To: Matthew Wilcox Cc: Christoph Hellwig , Andrew Morton , Souptick Joarder , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Alex Shi Subject: Re: [PATCH] mm: add prototype for __add_to_page_cache_locked() Message-ID: <20201223155254.GA6138@infradead.org> References: <1608646792-29073-1-git-send-email-jrdr.linux@gmail.com> <20201222204000.GN874@casper.infradead.org> <20201222155345.e7086ad37967c9b7feae29e4@linux-foundation.org> <20201223083126.GA27049@infradead.org> <20201223121136.GP874@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201223121136.GP874@casper.infradead.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 23, 2020 at 12:11:36PM +0000, Matthew Wilcox wrote: > On Wed, Dec 23, 2020 at 08:31:26AM +0000, Christoph Hellwig wrote: > > Can we please make the eBPF code stop referencing this function instead > > of papering over this crap? It has no business poking into page cache > > internals. > > The reference from the BPF code is simply "you can inject errors here". > And I think we want to be able to inject errors to test the error paths, > no? Something that expects a symbol to be global is just pretty broken. I think it need to change so that whatever instrumentation is done can coexist with a static function.