kernel.h: make abs() work with 64-bit types

[karo-tx-linux.git] / include / linux / kernel.h

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 5582410727cbf5cdb70bb1cba30729d7ebf4aa26..05ce782d53ab2c196385494fcda0f683249ca467 100644 (file)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -200,28 +200,31 @@ extern int _cond_resched(void);
 
 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 
-/*
- * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
- * input types abs() returns a signed long.
- * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
- * for those.
+/**
+ * abs - return absolute value of an argument
+ * @x: the value.  If it is unsigned type, it is converted to signed type first
+ *   (s64, long or int depending on its size).
+ *
+ * Return: an absolute value of x.  If x is 64-bit, macro's return type is s64,
+ *   otherwise it is signed long.
  */
-#define abs(x) ({                                              \
-               long ret;                                       \
-               if (sizeof(x) == sizeof(long)) {                \
-                       long __x = (x);                         \
-                       ret = (__x < 0) ? -__x : __x;           \
-               } else {                                        \
-                       int __x = (x);                          \
-                       ret = (__x < 0) ? -__x : __x;           \
-               }                                               \
-               ret;                                            \
-       })
-
-#define abs64(x) ({                            \
-               s64 __x = (x);                  \
-               (__x < 0) ? -__x : __x;         \
-       })
+#define abs(x) __builtin_choose_expr(sizeof(x) == sizeof(s64), ({      \
+               s64 __x = (x);                                          \
+               (__x < 0) ? -__x : __x;                                 \
+       }), ({                                                          \
+               long ret;                                               \
+               if (sizeof(x) == sizeof(long)) {                        \
+                       long __x = (x);                                 \
+                       ret = (__x < 0) ? -__x : __x;                   \
+               } else {                                                \
+                       int __x = (x);                                  \
+                       ret = (__x < 0) ? -__x : __x;                   \
+               }                                                       \
+               ret;                                                    \
+       }))
+
+/* Deprecated, use abs instead. */
+#define abs64(x) abs((s64)(x))
 
 /**
  * reciprocal_scale - "scale" a value into range [0, ep_ro)
@@ -413,6 +416,8 @@ extern __printf(2, 3)
 char *kasprintf(gfp_t gfp, const char *fmt, ...);
 extern __printf(2, 0)
 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
+extern __printf(2, 0)
+const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
 
 extern __scanf(2, 3)
 int sscanf(const char *, const char *, ...);