Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
lib: count_zeros: unify count_{leading,trailing}_zeros()
The 'leading' helper returns BITS_PER_LONG if x == 0, while 'trailing'
one returns COUNT_TRAILING_ZEROS_0, which turns to be -1.
None of the current users explicitly check the returned value for
COUNT_TRAILING_ZEROS_0, except the loongarch, which tests implicitly
for the '>= 0'.
So, align count_trailing_zeros() with the count_leading_zeros(), and
simplify the loongarch handling.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Yury Norov <ynorov@nvidia.com>
+4
-6
+2
-2
arch/loongarch/kvm/intc/eiointc.c
+2
-2
arch/loongarch/kvm/intc/eiointc.c
···
16
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ipnum = (s->ipmap >> (irq / 32 * 8)) & 0xff;
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if (!(s->status & BIT(EIOINTC_ENABLE_INT_ENCODE))) {
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ipnum = count_trailing_zeros(ipnum);
19
-
ipnum = (ipnum >= 0 && ipnum < 4) ? ipnum : 0;
19
+
ipnum = ipnum < 4 ? ipnum : 0;
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}
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21
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22
cpuid = ((u8 *)s->coremap)[irq];
···
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ipnum = (s->ipmap >> (irq / 32 * 8)) & 0xff;
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if (!(s->status & BIT(EIOINTC_ENABLE_INT_ENCODE))) {
43
43
ipnum = count_trailing_zeros(ipnum);
44
-
ipnum = (ipnum >= 0 && ipnum < 4) ? ipnum : 0;
44
+
ipnum = ipnum < 4 ? ipnum : 0;
45
45
}
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cpu = s->sw_coremap[irq];
+2
-4
include/linux/count_zeros.h
+2
-4
include/linux/count_zeros.h
···
10
10
11
11
#include <asm/bitops.h>
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13
-
#define COUNT_TRAILING_ZEROS_0 (-1)
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-
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/**
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* count_leading_zeros - Count the number of zeros from the MSB back
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15
* @x: The value
···
36
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*
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* If the LSB of @x is set, the result is 0.
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* If only the MSB of @x is set, then the result is BITS_PER_LONG-1.
39
-
* If @x is 0 then the result is COUNT_TRAILING_ZEROS_0.
41
+
* If @x is 0 then the result is BITS_PER_LONG.
40
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*/
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static inline int count_trailing_zeros(unsigned long x)
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{
43
-
return (x != 0) ? __ffs(x) : COUNT_TRAILING_ZEROS_0;
45
+
return x ? __ffs(x) : BITS_PER_LONG;
44
46
}
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48
#endif /* _LINUX_BITOPS_COUNT_ZEROS_H_ */