Passing 0 to roundup_pow_of_two would lead to wrapping around and trying to find the last set bit on (unsigned long)(-1), which is obviously wrong.
Instead, deal with this case by rounding it up to the closest power of two (2 ** 0). Signed-off-by: Sasha Levin <[email protected]> --- include/linux/log2.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/log2.h b/include/linux/log2.h index fd7ff3d..b6bdf0c 100644 --- a/include/linux/log2.h +++ b/include/linux/log2.h @@ -60,6 +60,9 @@ bool is_power_of_2(unsigned long n) static inline __attribute__((const)) unsigned long __roundup_pow_of_two(unsigned long n) { + if (n == 0) + return 1UL << 0; + return 1UL << fls_long(n - 1); } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
