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From: Nitin Gupta <nitin.m.gupta@oracle.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: "David S. Miller" <davem@davemloft.net>,
	Nitin Gupta <nitin.m.gupta@oracle.com>,
	Lorenzo Stoakes <lstoakes@gmail.com>, Jan Kara <jack@suse.cz>,
	Michal Hocko <mhocko@suse.com>,
	sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] sparc64: Fix gup_huge_pmd
Date: Wed, 21 Jun 2017 14:50:09 -0700	[thread overview]
Message-ID: <1498081816-179369-1-git-send-email-nitin.m.gupta@oracle.com> (raw)

The function assumes that each PMD points to head of a
huge page. This is not correct as a PMD can point to
start of any 8M region with a, say 256M, hugepage. The
fix ensures that it points to the correct head of any PMD
huge page.

Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
---
 arch/sparc/mm/gup.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index cd0e32b..9116a6f 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -80,6 +80,8 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
 	refs = 0;
 	head = pmd_page(pmd);
 	page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
+	if (PageTail(head))
+		head = compound_head(head);
 	do {
 		VM_BUG_ON(compound_head(page) != head);
 		pages[*nr] = page;
-- 
2.9.2

WARNING: multiple messages have this Message-ID (diff)
From: Nitin Gupta <nitin.m.gupta@oracle.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: Nitin Gupta <nitin.m.gupta@oracle.com>,
	Lorenzo Stoakes <lstoakes@gmail.com>, Jan Kara <jack@suse.cz>,
	Michal Hocko <mhocko@suse.com>,
	sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] sparc64: Fix gup_huge_pmd
Date: Wed, 21 Jun 2017 21:50:09 +0000	[thread overview]
Message-ID: <1498081816-179369-1-git-send-email-nitin.m.gupta@oracle.com> (raw)

The function assumes that each PMD points to head of a
huge page. This is not correct as a PMD can point to
start of any 8M region with a, say 256M, hugepage. The
fix ensures that it points to the correct head of any PMD
huge page.

Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
---
 arch/sparc/mm/gup.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index cd0e32b..9116a6f 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -80,6 +80,8 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
 	refs = 0;
 	head = pmd_page(pmd);
 	page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
+	if (PageTail(head))
+		head = compound_head(head);
 	do {
 		VM_BUG_ON(compound_head(page) != head);
 		pages[*nr] = page;
-- 
2.9.2


             reply	other threads:[~2017-06-21 21:50 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-21 21:50 Nitin Gupta [this message]
2017-06-21 21:50 ` [PATCH] sparc64: Fix gup_huge_pmd Nitin Gupta
2017-06-22 10:53 ` Julian Calaby
2017-06-22 10:53   ` Julian Calaby
2017-06-22 14:37   ` Nitin Gupta
2017-06-22 14:37     ` Nitin Gupta
2017-06-22 14:45     ` Julian Calaby
2017-06-22 14:45       ` Julian Calaby

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