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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 32C79C2BCA1 for ; Fri, 7 Jun 2019 10:28:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 140F2212F5 for ; Fri, 7 Jun 2019 10:28:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728073AbfFGK25 (ORCPT ); Fri, 7 Jun 2019 06:28:57 -0400 Received: from foss.arm.com ([217.140.110.172]:37440 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726939AbfFGK24 (ORCPT ); Fri, 7 Jun 2019 06:28:56 -0400 X-Greylist: delayed 339 seconds by postgrey-1.27 at vger.kernel.org; Fri, 07 Jun 2019 06:28:56 EDT Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 89E85360; Fri, 7 Jun 2019 03:23:17 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C9D5C3F246; Fri, 7 Jun 2019 03:24:56 -0700 (PDT) Date: Fri, 7 Jun 2019 11:23:11 +0100 From: Mark Rutland To: Anshuman Khandual Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , James Morse , Andrey Konovalov , Christoph Hellwig Subject: Re: [PATCH V3 2/2] arm64/mm: Refactor __do_page_fault() Message-ID: <20190607102310.GA15753@lakrids.cambridge.arm.com> References: <1559898786-28530-1-git-send-email-anshuman.khandual@arm.com> <1559898786-28530-3-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1559898786-28530-3-git-send-email-anshuman.khandual@arm.com> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 07, 2019 at 02:43:06PM +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. > > Signed-off-by: Anshuman Khandual > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Mark Rutland > Cc: James Morse > Cc: Andrey Konovalov > Cc: Christoph Hellwig This keeps the existing behaviour, and is certainly cleaner, so: Reviewed-by: Mark Rutland Mark. > --- > arch/arm64/mm/fault.c | 30 +++++++++++------------------- > 1 file changed, 11 insertions(+), 19 deletions(-) > > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 95cac4a..235b7c0 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; > + } > + > /* > * Check that the permissions on the VMA allow for the fault which > * occurred. > */ > - if (!(vma->vm_flags & vm_flags)) { > - fault = VM_FAULT_BADACCESS; > - goto out; > - } > - > + if (!(vma->vm_flags & vm_flags)) > + return VM_FAULT_BADACCESS; > return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags); > - > -check_stack: > - if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) > - goto good_area; > -out: > - return fault; > } > > static bool is_el0_instruction_abort(unsigned int esr) > -- > 2.7.4 >