linux-kernel - [tip:x86/pat] x86, PAT: Change order of cpa and free in set_memory

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Date:	Fri, 10 Apr 2009 12:34:09 GMT
From:	"venkatesh.pallipadi@...el.com" <venkatesh.pallipadi@...el.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	venkatesh.pallipadi@...el.com, suresh.b.siddha@...el.com,
	tglx@...utronix.de, mingo@...e.hu
Subject: [tip:x86/pat] x86, PAT: Change order of cpa and free in set_memory_wb

Commit-ID:  a5593e0b329a14dea41ea173380dbf1533de2bd2
Gitweb:     http://git.kernel.org/tip/a5593e0b329a14dea41ea173380dbf1533de2bd2
Author:     venkatesh.pallipadi@...el.com <venkatesh.pallipadi@...el.com>
AuthorDate: Thu, 9 Apr 2009 14:26:48 -0700
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 10 Apr 2009 13:55:46 +0200

x86, PAT: Change order of cpa and free in set_memory_wb

To be free of aliasing due to races, set_memory_* interfaces should
follow ordering of reserving, changing memtype to UC/WC, changing
memtype back to WB followed by free.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com>
LKML-Reference: <20090409212708.512280000@...el.com>
Signed-off-by: Ingo Molnar <mingo@...e.hu>


---
 arch/x86/mm/pageattr.c |   11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index d71e1b6..d487eaa 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1021,15 +1021,19 @@ int _set_memory_wb(unsigned long addr, int numpages)
 
 int set_memory_wb(unsigned long addr, int numpages)
 {
+	int ret = _set_memory_wb(addr, numpages);
 	free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
-
-	return _set_memory_wb(addr, numpages);
+	return ret;
 }
 EXPORT_SYMBOL(set_memory_wb);
 
 int set_memory_array_wb(unsigned long *addr, int addrinarray)
 {
 	int i;
+	int ret;
+
+	ret = change_page_attr_clear(addr, addrinarray,
+				      __pgprot(_PAGE_CACHE_MASK), 1);
 
 	for (i = 0; i < addrinarray; i++) {
 		unsigned long start = __pa(addr[i]);
@@ -1042,8 +1046,7 @@ int set_memory_array_wb(unsigned long *addr, int addrinarray)
 		}
 		free_memtype(start, end);
 	}
-	return change_page_attr_clear(addr, addrinarray,
-				      __pgprot(_PAGE_CACHE_MASK), 1);
+	return ret;
 }
 EXPORT_SYMBOL(set_memory_array_wb);
 
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