Le 11/04/2018 ? 10:03, Laurent Dufour a ?crit?:
> 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 <ldufour at linux.vnet.ibm.com>
> ---
> mm/memory.c | 19 ++++++++-----------
> 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,
> * PFNMAP mappings in order to support COWable mappings.
> *
> */
> -#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
> -# define HAVE_PTE_SPECIAL 1
> -#else
> -# define HAVE_PTE_SPECIAL 0
> -#endif
> struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
> pte_t pte, bool with_public_device)
> {
> unsigned long pfn = pte_pfn(pte);
>
> - if (HAVE_PTE_SPECIAL) {
> + if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) {
> if (likely(!pte_special(pte)))
> goto check_pfn;
> 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,
> return NULL;
> }
>
> - /* !HAVE_PTE_SPECIAL case follows: */
> + /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */
>
> if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
> if (vma->vm_flags & VM_MIXEDMAP) {
> @@ -881,7 +876,8 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
>
> if (is_zero_pfn(pfn))
> return NULL;
> -check_pfn:
> +
> +check_pfn: __maybe_unused
See below
> if (unlikely(pfn > highest_memmap_pfn)) {
> print_bad_pte(vma, addr, pte, NULL);
> return NULL;
> @@ -891,7 +887,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
> * NOTE! We still have PageReserved() pages in the page tables.
> * eg. VDSO mappings can cause them to exist.
> */
> -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.
Christophe
> return pfn_to_page(pfn);
> }
>
> @@ -904,7 +900,7 @@ struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
> /*
> * There is no pmd_special() but there may be special pmds, e.g.
> * in a direct-access (dax) mapping, so let's just replicate the
> - * !HAVE_PTE_SPECIAL case from vm_normal_page() here.
> + * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here.
> */
> if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
> if (vma->vm_flags & VM_MIXEDMAP) {
> @@ -1933,7 +1929,8 @@ static int __vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
> * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
> * without pte special, it would there be refcounted as a normal page.
> */
> - if (!HAVE_PTE_SPECIAL && !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) {
> + if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) &&
> + !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) {
> struct page *page;
>
> /*
>
