From: Jan Beulich Date: Fri, 6 Jul 2012 14:07:48 +0000 (+0100) Subject: x86/mm/mtrr: Fix alignment determination in range_to_mtrr() X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=1ba9a294141b106b7247649a5c3372d8284eca80;p=linux-beck.git 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 Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Cc: Yinghai Lu Link: http://lkml.kernel.org/r/4FF70D54020000780008E179@nat28.tlf.novell.com Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c index bdda2e6c673b..35ffda5d0727 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;