Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752220AbbGMPCl (ORCPT ); Mon, 13 Jul 2015 11:02:41 -0400 Received: from mga02.intel.com ([134.134.136.20]:7210 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751760AbbGMPCh (ORCPT ); Mon, 13 Jul 2015 11:02:37 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,463,1432623600"; d="scan'208";a="763511707" Date: Mon, 13 Jul 2015 11:02:35 -0400 From: Matthew Wilcox To: Jeff Moyer Cc: Matthew Wilcox , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 06/10] mm: Add vmf_insert_pfn_pmd() Message-ID: <20150713150235.GG13681@linux.intel.com> References: <1436560165-8943-1-git-send-email-matthew.r.wilcox@intel.com> <1436560165-8943-7-git-send-email-matthew.r.wilcox@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2223 Lines: 56 On Mon, Jul 13, 2015 at 09:23:41AM -0400, Jeff Moyer wrote: > Matthew Wilcox writes: > > > +static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, > > + pmd_t *pmd, unsigned long pfn, pgprot_t prot, bool write) > > +{ > > + return VM_FAULT_NOPAGE; > > +} > > What's the point of the return value? Good point. Originally, it paralleled insert_pfn() in mm/memory.c, but it became apparent that the return code of 0 or -Exxx was useless, and in converting insert_pfn_pmd over to VM_FAULT_ codes, all possible return codes were going to be VM_FAULT_NOPAGE. It didn't occur to me to take it one step further and make the function return void. It doesn't make much difference either way: diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 26d0fc1..5ffdcaa 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -837,7 +837,7 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, return 0; } -static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, +static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned long pfn, pgprot_t prot, bool write) { struct mm_struct *mm = vma->vm_mm; @@ -855,7 +855,6 @@ static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, update_mmu_cache_pmd(vma, addr, pmd); } spin_unlock(ptl); - return VM_FAULT_NOPAGE; } int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, @@ -877,7 +876,8 @@ int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, return VM_FAULT_SIGBUS; if (track_pfn_insert(vma, &pgprot, pfn)) return VM_FAULT_SIGBUS; - return insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write); + insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write); + return VM_FAULT_NOPAGE; } int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, I suppose it's slightly cleaner. I'll integrate this for the next release. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/