X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=include%2Flinux%2Flog2.h;h=99922bedfcc90acaef644369aee3d5e126b7d46d;hb=5986a2ec35836a878350c54af4bd91b1de6abc59;hp=d02e1a547a7e9deb1e8bc21857780bdc2c7693c0;hpb=13d7d84e078f49f08b657a3fba0d7a0b7b44ba65;p=linux-2.6

diff --git a/include/linux/log2.h b/include/linux/log2.h
index d02e1a547a..99922bedfc 100644
--- a/include/linux/log2.h
+++ b/include/linux/log2.h
@@ -43,6 +43,17 @@ int __ilog2_u64(u64 n)
 }
 #endif
 
+/*
+ *  Determine whether some value is a power of two, where zero is
+ * *not* considered a power of two.
+ */
+
+static inline __attribute__((const))
+bool is_power_of_2(unsigned long n)
+{
+	return (n != 0 && ((n & (n - 1)) == 0));
+}
+
 /*
  * round up to nearest power of two
  */