From patchwork Fri Jan 28 17:30:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 537799 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 857C9C4332F for ; Fri, 28 Jan 2022 17:30:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343610AbiA1RaN (ORCPT ); Fri, 28 Jan 2022 12:30:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57172 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343672AbiA1RaM (ORCPT ); Fri, 28 Jan 2022 12:30:12 -0500 Received: from xavier.telenet-ops.be (xavier.telenet-ops.be [IPv6:2a02:1800:120:4::f00:14]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9A7DC06173B for ; Fri, 28 Jan 2022 09:30:11 -0800 (PST) Received: from ramsan.of.borg ([IPv6:2a02:1810:ac12:ed40:3999:e79d:cb59:f2ec]) by xavier.telenet-ops.be with bizsmtp id oHW92600704fKGS01HW9pQ; Fri, 28 Jan 2022 18:30:09 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan.of.borg with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nDV4a-00C0CU-Vh; Fri, 28 Jan 2022 18:30:08 +0100 Received: from geert by rox.of.borg with local (Exim 4.93) (envelope-from ) id 1nDV4a-007BhB-EK; Fri, 28 Jan 2022 18:30:08 +0100 From: Geert Uytterhoeven To: linux-m68k@lists.linux-m68k.org Cc: Andrew Morton , linux-mm@kvack.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH] m68k: mm: Remove check for VM_IO to fix deferred I/O Date: Fri, 28 Jan 2022 18:30:06 +0100 Message-Id: <20220128173006.1713210-1-geert@linux-m68k.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org When an application accesses a mapped frame buffer backed by deferred I/O, it receives a segmentation fault. Fix this by removing the check for VM_IO in do_page_fault(). Signed-off-by: Geert Uytterhoeven Tested-by: Michael Schmitz --- This check was never present in a fault handler on any other architecture than m68k. Some digging revealed that it was added in v2.1.106, but I couldn't find an email with a patch adding it. That same kernel version extended the use of the hwreg_present() helper to HP9000/300, so the check might have been needed there, perhaps only during development? The Atari kernel relies heavily on hwreg_present() (both the success and failure cases), and these still work, at least on ARAnyM. --- arch/m68k/mm/fault.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c index 1493cf5eac1e7a39..71aa9f6315dc8028 100644 --- a/arch/m68k/mm/fault.c +++ b/arch/m68k/mm/fault.c @@ -93,8 +93,6 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, vma = find_vma(mm, address); if (!vma) goto map_err; - if (vma->vm_flags & VM_IO) - goto acc_err; if (vma->vm_start <= address) goto good_area; if (!(vma->vm_flags & VM_GROWSDOWN))