minmax.h: remove some #defines that are only expanded once

The bodies of __signed_type_use() and __unsigned_type_use() are much the
same size as their names - so put the bodies in the only line that expands
them.

Similarly __signed_type() is defined separately for 64bit and then used
exactly once just below.

Change the test for __signed_type from CONFIG_64BIT to one based on gcc
defined macros so that the code is valid if it gets used outside of a
kernel build.

Link: https://lkml.kernel.org/r/9386d1ebb8974fbabbed2635160c3975@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: david-laight

include/linux/minmax.h

@@ -46,18 +46,16 @@
  * comparison, and these expressions only need to be careful to not cause
  * warnings for pointer use.
  */
-#define __signed_type_use(ux) (2 + __is_nonneg(ux))
-#define __unsigned_type_use(ux) (1 + 2 * (sizeof(ux) < 4))
 #define __sign_use(ux) (is_signed_type(typeof(ux)) ? \
-	__signed_type_use(ux) : __unsigned_type_use(ux))
+	(2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
 
 /*
  * Check whether a signed value is always non-negative.
  *
  * A cast is needed to avoid any warnings from values that aren't signed
  * integer types (in which case the result doesn't matter).
  *
- * On 64-bit any integer or pointer type can safely be cast to 'long'.
+ * On 64-bit any integer or pointer type can safely be cast to 'long long'.
  * But on 32-bit we need to avoid warnings about casting pointers to integers
  * of different sizes without truncating 64-bit values so 'long' or 'long long'
  * must be used depending on the size of the value.
@@ -66,12 +64,12 @@
  * them, but we do not use s128 types in the kernel (we do use 'u128',
  * but they are handled by the !is_signed_type() case).
  */
-#ifdef CONFIG_64BIT
-  #define __signed_type(ux) long
+#if __SIZEOF_POINTER__ == __SIZEOF_LONG_LONG__
+#define __is_nonneg(ux) statically_true((long long)(ux) >= 0)
 #else
-  #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L))
+#define __is_nonneg(ux) statically_true( \
+	(typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)))(ux) >= 0)
 #endif
-#define __is_nonneg(ux) statically_true((__signed_type(ux))(ux) >= 0)
 
 #define __types_ok(ux, uy) \
 	(__sign_use(ux) & __sign_use(uy))