module: LLVMLinux: Remove unused function warning from __param_check macro
authorMark Charlebois <charlebm@gmail.com>
Mon, 17 Mar 2014 02:48:26 +0000 (13:18 +1030)
committerRusty Russell <rusty@rustcorp.com.au>
Mon, 17 Mar 2014 04:24:50 +0000 (14:54 +1030)
commit0283f9a529c81e64bafea80d6d3e056d1c3f656d
tree731d8732ecdf213c44b7e61e44d9e636b93d2a9d
parent66cc69e34e86a231fbe68d8918c6119e3b7549a3
module: LLVMLinux: Remove unused function warning from __param_check macro

This code makes a compile time type check that is optimized away. Clang
complains that it generates an unused function:

linux/kernel/panic.c:471:1: warning: unused function '__check_panic'
      [-Wunused-function]
core_param(panic, panic_timeout, int, 0644);
^
linux/moduleparam.h:283:2: note: expanded from macro
      'core_param'
        param_check_##type(name, &(var));                               \
        ^
<scratch space>:87:1: note: expanded from here
param_check_int
^
linux/moduleparam.h:369:34: note: expanded from macro
      'param_check_int'
#define param_check_int(name, p) __param_check(name, p, int)
                                 ^
linux/moduleparam.h:349:22: note: expanded from macro
      '__param_check'
        static inline type *__check_##name(void) { return(p); }
                            ^
<scratch space>:88:1: note: expanded from here
__check_panic

GCC won't complain for a static inline function but would if it was just
a static function.

Adding the unused attribute to the function declaration removes the warning.
Per request from Rusty Russell it is marked as __always_unused as the code
is meant to be optimized away.

This code works for both GCC and clang.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
include/linux/moduleparam.h