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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 3E059C282CE for ; Tue, 4 Jun 2019 14:56:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 176C723426 for ; Tue, 4 Jun 2019 14:56:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727825AbfFDO4S (ORCPT ); Tue, 4 Jun 2019 10:56:18 -0400 Received: from foss.arm.com ([217.140.101.70]:45960 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727574AbfFDO4R (ORCPT ); Tue, 4 Jun 2019 10:56:17 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E82BC341; Tue, 4 Jun 2019 07:56:16 -0700 (PDT) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 664F33F690; Tue, 4 Jun 2019 07:56:15 -0700 (PDT) Date: Tue, 4 Jun 2019 15:56:12 +0100 From: Catalin Marinas To: Anshuman Khandual Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Will Deacon , Mark Rutland , James Morse , Andrey Konovalov , Christoph Hellwig Subject: Re: [PATCH V2 4/4] arm64/mm: Drop local variable vm_fault_t from __do_page_fault() Message-ID: <20190604145612.GM6610@arrakis.emea.arm.com> References: <1559544085-7502-1-git-send-email-anshuman.khandual@arm.com> <1559544085-7502-5-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1559544085-7502-5-git-send-email-anshuman.khandual@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 03, 2019 at 12:11:25PM +0530, Anshuman Khandual wrote: > __do_page_fault() is over complicated with multiple goto statements. This > cleans up the code flow and while there drops local variable vm_fault_t. I'd change the subject as well here to something like refactor or simplify __do_page_fault(). > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 4bb65f3..41fa905 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -397,37 +397,29 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re > static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, > unsigned int mm_flags, unsigned long vm_flags) > { > - struct vm_area_struct *vma; > - vm_fault_t fault; > + struct vm_area_struct *vma = find_vma(mm, addr); > > - vma = find_vma(mm, addr); > - fault = VM_FAULT_BADMAP; > if (unlikely(!vma)) > - goto out; > - if (unlikely(vma->vm_start > addr)) > - goto check_stack; > + return VM_FAULT_BADMAP; > > /* > * Ok, we have a good vm_area for this memory access, so we can handle > * it. > */ > -good_area: > + if (unlikely(vma->vm_start > addr)) { > + if (!(vma->vm_flags & VM_GROWSDOWN)) > + return VM_FAULT_BADMAP; > + if (expand_stack(vma, addr)) > + return VM_FAULT_BADMAP; > + } You could have a single return here: if (unlikely(vma->vm_start > addr) && (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack(vma, addr))) return VM_FAULT_BADMAP; Not sure it's any clearer though. -- Catalin