From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: [PATCH 06/10] mm: Add vmf_insert_pfn_pmd() Date: Mon, 13 Jul 2015 11:02:35 -0400 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 Cc: Matthew Wilcox , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org To: Jeff Moyer Return-path: Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org