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Violators will be prosecuted for from ; Wed, 11 Apr 2018 10:03:47 +0100 Subject: Re: [PATCH v3 2/2] mm: remove odd HAVE_PTE_SPECIAL References: <1523433816-14460-1-git-send-email-ldufour@linux.vnet.ibm.com> <1523433816-14460-3-git-send-email-ldufour@linux.vnet.ibm.com> From: Laurent Dufour Date: Wed, 11 Apr 2018 11:03:37 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Message-Id: <93ed4fe4-dd1e-51be-948b-d53b16de21c5@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Christophe LEROY , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, Jerome Glisse , mhocko@kernel.org, aneesh.kumar@linux.vnet.ibm.com, akpm@linux-foundation.org, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, Jonathan Corbet , Catalin Marinas , Will Deacon , Yoshinori Sato , Rich Felker , "David S . Miller" , Thomas Gleixner , Ingo Molnar , Vineet Gupta , Palmer Dabbelt , Albert Ou , Martin Schwidefsky , Heiko Carstens , David Rientjes , Robin Murphy On 11/04/2018 10:58, Christophe LEROY wrote: > > > Le 11/04/2018 A 10:03, Laurent Dufour a A(C)critA : >> Remove the additional define HAVE_PTE_SPECIAL and rely directly on >> CONFIG_ARCH_HAS_PTE_SPECIAL. >> >> There is no functional change introduced by this patch >> >> Signed-off-by: Laurent Dufour >> --- >> A mm/memory.c | 19 ++++++++----------- >> A 1 file changed, 8 insertions(+), 11 deletions(-) >> >> diff --git a/mm/memory.c b/mm/memory.c >> index 96910c625daa..7f7dc7b2a341 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -817,17 +817,12 @@ static void print_bad_pte(struct vm_area_struct *vma, >> unsigned long addr, >> A A * PFNMAP mappings in order to support COWable mappings. >> A A * >> A A */ >> -#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL >> -# define HAVE_PTE_SPECIAL 1 >> -#else >> -# define HAVE_PTE_SPECIAL 0 >> -#endif >> A struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr, >> A A A A A A A A A A A A A A A A A A pte_t pte, bool with_public_device) >> A { >> A A A A A unsigned long pfn = pte_pfn(pte); >> A -A A A if (HAVE_PTE_SPECIAL) { >> +A A A if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) { >> A A A A A A A A A if (likely(!pte_special(pte))) >> A A A A A A A A A A A A A goto check_pfn; >> A A A A A A A A A if (vma->vm_ops && vma->vm_ops->find_special_page) >> @@ -862,7 +857,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, >> unsigned long addr, >> A A A A A A A A A return NULL; >> A A A A A } >> A -A A A /* !HAVE_PTE_SPECIAL case follows: */ >> +A A A /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */ >> A A A A A A if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { >> A A A A A A A A A if (vma->vm_flags & VM_MIXEDMAP) { >> @@ -881,7 +876,8 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, >> unsigned long addr, >> A A A A A A if (is_zero_pfn(pfn)) >> A A A A A A A A A return NULL; >> -check_pfn: >> + >> +check_pfn: __maybe_unused > > See below > >> A A A A A if (unlikely(pfn > highest_memmap_pfn)) { >> A A A A A A A A A print_bad_pte(vma, addr, pte, NULL); >> A A A A A A A A A return NULL; >> @@ -891,7 +887,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, >> unsigned long addr, >> A A A A A A * NOTE! We still have PageReserved() pages in the page tables. >> A A A A A A * eg. VDSO mappings can cause them to exist. >> A A A A A A */ >> -out: >> +out: __maybe_unused > > Why do you need that change ? > > There is no reason for the compiler to complain. It would complain if the goto > was within a #ifdef, but all the purpose of using IS_ENABLED() is to allow the > compiler to properly handle all possible cases. That's all the force of > IS_ENABLED() compared to ifdefs, and that the reason why they are plebicited, > ref Linux Codying style for a detailed explanation. Fair enough. Should I submit a v4 just to remove these so ugly __maybe_unused ?