Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
lib: crypto: fix comments for count_leading_zeros()
count_leading_zeros() is based on fls(), which is defined for x == 0,
contrary to __ffs() family. The comment in crypto/mpi erroneously
states that the function may return undef in such case.
Fix the comment together with the outdated function signature, and now
that COUNT_LEADING_ZEROS_0 is not referenced in the codebase, get rid of
it too.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Yury Norov <ynorov@nvidia.com>
+5
-7
+1
-3
include/linux/count_zeros.h
+1
-3
include/linux/count_zeros.h
···
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*
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* If the MSB of @x is set, the result is 0.
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* If only the LSB of @x is set, then the result is BITS_PER_LONG-1.
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-
* If @x is 0 then the result is COUNT_LEADING_ZEROS_0.
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+
* If @x is 0 then the result is BITS_PER_LONG.
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*/
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static inline int count_leading_zeros(unsigned long x)
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{
···
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else
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return BITS_PER_LONG - fls64(x);
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}
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-
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-
#define COUNT_LEADING_ZEROS_0 BITS_PER_LONG
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/**
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* count_trailing_zeros - Count the number of zeros from the LSB forwards
+4
-4
lib/crypto/mpi/longlong.h
+4
-4
lib/crypto/mpi/longlong.h
···
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* denominator). Like udiv_qrnnd but the numbers are signed. The quotient
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* is rounded towards 0.
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*
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-
* 5) count_leading_zeros(count, x) counts the number of zero-bits from the
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+
* 5) count_leading_zeros(x) counts the number of zero-bits from the
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* msb to the first non-zero bit in the UWtype X. This is the number of
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-
* steps X needs to be shifted left to set the msb. Undefined for X == 0,
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-
* unless the symbol COUNT_LEADING_ZEROS_0 is defined to some value.
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+
* steps X needs to be shifted left to set the msb.
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+
* count_leading_zeros(0) == BITS_PER_LONG
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*
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-
* 6) count_trailing_zeros(count, x) like count_leading_zeros, but counts
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+
* 6) count_trailing_zeros() like count_leading_zeros(), but counts
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* from the least significant end.
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*
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* 7) add_ssaaaa(high_sum, low_sum, high_addend_1, low_addend_1,