[tip:x86/asm] x86/mm/mtrr: Fix alignment determination in range_to_mtrr()
From: tip-bot for Jan Beulich
Date: Tue Jul 10 2012 - 05:56:19 EST
Commit-ID: 1ba9a294141b106b7247649a5c3372d8284eca80
Gitweb: http://git.kernel.org/tip/1ba9a294141b106b7247649a5c3372d8284eca80
Author: Jan Beulich <JBeulich@xxxxxxxx>
AuthorDate: Fri, 6 Jul 2012 15:07:48 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 10 Jul 2012 10:38:14 +0200
x86/mm/mtrr: Fix alignment determination in range_to_mtrr()
With the variable operated on being of "unsigned long" type,
neither ffs() nor fls() are suitable to use on them, as those
truncate their arguments to 32 bits. Using __ffs() and __fls()
respectively at once eliminates the need to subtract 1 from their
results.
Additionally, with the alignment value subsequently used as a
shift count, it must be enforced to be less than BITS_PER_LONG
(and on 64-bit there's no need for it to be any smaller).
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/4FF70D54020000780008E179@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/cpu/mtrr/cleanup.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
index bdda2e6..35ffda5 100644
--- a/arch/x86/kernel/cpu/mtrr/cleanup.c
+++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
@@ -258,11 +258,11 @@ range_to_mtrr(unsigned int reg, unsigned long range_startk,
/* Compute the maximum size with which we can make a range: */
if (range_startk)
- max_align = ffs(range_startk) - 1;
+ max_align = __ffs(range_startk);
else
- max_align = 32;
+ max_align = BITS_PER_LONG - 1;
- align = fls(range_sizek) - 1;
+ align = __fls(range_sizek);
if (align > max_align)
align = max_align;
--
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