linux-kernel - [tip:x86/mm] x86/mm: Fix gup_huge

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Message-ID: <tip-daf3e35c5888e8bd6a2f5ed15ed392b2df362ecf@git.kernel.org>
Date:	Tue, 22 Sep 2015 12:44:57 -0700
From:	tip-bot for Toshi Kani <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	mingo@...hat.com, elliott@....com, mingo@...nel.org, hpa@...or.com,
	konrad.wilk@...cle.com, tglx@...utronix.de, bp@...en8.de,
	toshi.kani@....com, linux-kernel@...r.kernel.org, jgross@...e.com,
	akpm@...ux-foundation.org
Subject: [tip:x86/mm] x86/mm: Fix gup_huge_p?d() to handle large PAT bit

Commit-ID:  daf3e35c5888e8bd6a2f5ed15ed392b2df362ecf
Gitweb:     http://git.kernel.org/tip/daf3e35c5888e8bd6a2f5ed15ed392b2df362ecf
Author:     Toshi Kani <toshi.kani@....com>
AuthorDate: Thu, 17 Sep 2015 12:24:21 -0600
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Tue, 22 Sep 2015 21:27:33 +0200

x86/mm: Fix gup_huge_p?d() to handle large PAT bit

gup_huge_pud() and gup_huge_pmd() cast *pud and *pmd to *pte,
and use pte_xxx() interfaces to obtain the flags and PFN.
However, the pte_xxx() interface does not handle the large
PAT bit properly for PUD/PMD.

Fix gup_huge_pud() and gup_huge_pmd() to use pud_xxx() and
pmd_xxx() interfaces according to their type.

Signed-off-by: Toshi Kani <toshi.kani@....com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Juergen Gross <jgross@...e.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Konrad Wilk <konrad.wilk@...cle.com>
Cc: Robert Elliot <elliott@....com>
Cc: linux-mm@...ck.org
Link: http://lkml.kernel.org/r/1442514264-12475-9-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/mm/gup.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index 81bf3d2..ae9a37b 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -118,21 +118,20 @@ static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr,
 		unsigned long end, int write, struct page **pages, int *nr)
 {
 	unsigned long mask;
-	pte_t pte = *(pte_t *)&pmd;
 	struct page *head, *page;
 	int refs;
 
 	mask = _PAGE_PRESENT|_PAGE_USER;
 	if (write)
 		mask |= _PAGE_RW;
-	if ((pte_flags(pte) & mask) != mask)
+	if ((pmd_flags(pmd) & mask) != mask)
 		return 0;
 	/* hugepages are never "special" */
-	VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
-	VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
+	VM_BUG_ON(pmd_flags(pmd) & _PAGE_SPECIAL);
+	VM_BUG_ON(!pfn_valid(pmd_pfn(pmd)));
 
 	refs = 0;
-	head = pte_page(pte);
+	head = pmd_page(pmd);
 	page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
 	do {
 		VM_BUG_ON_PAGE(compound_head(page) != head, page);
@@ -195,21 +194,20 @@ static noinline int gup_huge_pud(pud_t pud, unsigned long addr,
 		unsigned long end, int write, struct page **pages, int *nr)
 {
 	unsigned long mask;
-	pte_t pte = *(pte_t *)&pud;
 	struct page *head, *page;
 	int refs;
 
 	mask = _PAGE_PRESENT|_PAGE_USER;
 	if (write)
 		mask |= _PAGE_RW;
-	if ((pte_flags(pte) & mask) != mask)
+	if ((pud_flags(pud) & mask) != mask)
 		return 0;
 	/* hugepages are never "special" */
-	VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
-	VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
+	VM_BUG_ON(pud_flags(pud) & _PAGE_SPECIAL);
+	VM_BUG_ON(!pfn_valid(pud_pfn(pud)));
 
 	refs = 0;
-	head = pte_page(pte);
+	head = pud_page(pud);
 	page = head + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
 	do {
 		VM_BUG_ON_PAGE(compound_head(page) != head, page);
--
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