linux-kernel - [PATCH v2 2/2] mm: remove odd HAVE_PTE

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Message-Id: <1523373951-10981-3-git-send-email-ldufour@linux.vnet.ibm.com>
Date:   Tue, 10 Apr 2018 17:25:51 +0200
From:   Laurent Dufour <ldufour@...ux.vnet.ibm.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        linuxppc-dev@...ts.ozlabs.org, x86@...nel.org,
        linux-doc@...r.kernel.org, linux-snps-arc@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org,
        linux-sh@...r.kernel.org, sparclinux@...r.kernel.org,
        Jerome Glisse <jglisse@...hat.com>, mhocko@...nel.org,
        aneesh.kumar@...ux.vnet.ibm.com, akpm@...ux-foundation.org,
        mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
        Jonathan Corbet <corbet@....net>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        "David S . Miller" <davem@...emloft.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Vineet Gupta <vgupta@...opsys.com>,
        Palmer Dabbelt <palmer@...ive.com>,
        Albert Ou <albert@...ive.com>,
        Martin Schwidefsky <schwidefsky@...ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        David Rientjes <rientjes@...gle.com>
Subject: [PATCH v2 2/2] mm: remove odd HAVE_PTE_SPECIAL

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@...ux.vnet.ibm.com>
---
 mm/memory.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 96910c625daa..53b6344a90d2 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -817,19 +817,13 @@ 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 (likely(!pte_special(pte)))
-			goto check_pfn;
+#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
+	if (unlikely(pte_special(pte))) {
 		if (vma->vm_ops && vma->vm_ops->find_special_page)
 			return vma->vm_ops->find_special_page(vma, addr);
 		if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
@@ -862,7 +856,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
 		return NULL;
 	}
 
-	/* !HAVE_PTE_SPECIAL case follows: */
+#else	/* CONFIG_ARCH_HAS_PTE_SPECIAL */
 
 	if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
 		if (vma->vm_flags & VM_MIXEDMAP) {
@@ -881,7 +875,8 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
 
 	if (is_zero_pfn(pfn))
 		return NULL;
-check_pfn:
+#endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */
+
 	if (unlikely(pfn > highest_memmap_pfn)) {
 		print_bad_pte(vma, addr, pte, NULL);
 		return NULL;
@@ -891,7 +886,7 @@ 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
 	return pfn_to_page(pfn);
 }
 
@@ -904,7 +899,7 @@ 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) {
@@ -1926,6 +1921,7 @@ static int __vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
 
 	track_pfn_insert(vma, &pgprot, pfn);
 
+#ifndef CONFIG_ARCH_HAS_PTE_SPECIAL
 	/*
 	 * If we don't have pte special, then we have to use the pfn_valid()
 	 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
@@ -1933,7 +1929,7 @@ 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 (!pfn_t_devmap(pfn) && pfn_t_valid(pfn)) {
 		struct page *page;
 
 		/*
@@ -1944,6 +1940,7 @@ static int __vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
 		page = pfn_to_page(pfn_t_to_pfn(pfn));
 		return insert_page(vma, addr, page, pgprot);
 	}
+#endif
 	return insert_pfn(vma, addr, pfn, pgprot, mkwrite);
 }
 
-- 
2.7.4