[3.13.y.z extended stable] Patch "sparc64: Fix bugs in get_user_pages_fast() wrt. THP." has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    sparc64: Fix bugs in get_user_pages_fast() wrt. THP.

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.7.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 504162bc0a4b347c28f6b5780887b063146ba00a Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem at davemloft.net>
Date: Fri, 25 Apr 2014 10:21:12 -0700
Subject: sparc64: Fix bugs in get_user_pages_fast() wrt. THP.

[ Upstream commit 04df419de34104d8818b8c5cffaa062fa36d20ea ]

The large PMD path needs to check _PAGE_VALID not _PAGE_PRESENT, to
decide if it needs to bail and return 0.

pmd_large() should therefore just check _PAGE_PMD_HUGE.

Calls to gup_huge_pmd() are guarded with a check of pmd_large(), so we
just need to add a valid bit check.

Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/sparc/include/asm/pgtable_64.h | 2 +-
 arch/sparc/mm/gup.c                 | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index e3db4b8..1f28103 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -633,7 +633,7 @@ static inline unsigned long pmd_large(pmd_t pmd)
 {
 	pte_t pte = __pte(pmd_val(pmd));

-	return (pte_val(pte) & _PAGE_PMD_HUGE) && pte_present(pte);
+	return pte_val(pte) & _PAGE_PMD_HUGE;
 }

 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index c4d3da6..1aed043 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -73,7 +73,7 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
 	struct page *head, *page, *tail;
 	int refs;

-	if (!pmd_large(pmd))
+	if (!(pmd_val(pmd) & _PAGE_VALID))
 		return 0;

 	if (write && !pmd_write(pmd))
--
1.9.1