Re: [PATCH] include/linux/rbtree.h: move the declaration of c in rb_find_add()

[kernel test robot <lkp@intel.com>]

Hi Lin,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.3-rc7 next-20230417]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Lin-Chun-Yeh/include-linux-rbtree-h-move-the-declaration-of-c-in-rb_find_add/20230418-230031
patch link:    https://lore.kernel.org/r/20230418145712.20620-1-r09921093%40g.ntu.edu.tw
patch subject: [PATCH] include/linux/rbtree.h: move the declaration of c in rb_find_add()
config: riscv-randconfig-r042-20230416 (https://download.01.org/0day-ci/archive/20230419/202304190113.SlgVhTbO-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/9348e5c71c46a8d88c805acf5dd56c1785bc04e8
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Lin-Chun-Yeh/include-linux-rbtree-h-move-the-declaration-of-c-in-rb_find_add/20230418-230031
        git checkout 9348e5c71c46a8d88c805acf5dd56c1785bc04e8
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash lib/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304190113.SlgVhTbO-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from include/linux/mm_types.h:11,
                    from include/linux/buildid.h:5,
                    from include/linux/module.h:14,
                    from lib/test_bitops.c:9:
   include/linux/rbtree.h: In function 'rb_find_add':
>> include/linux/rbtree.h:231:17: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
     231 |                 int c = cmp(node, parent);
         |                 ^~~
   cc1: all warnings being treated as errors


vim +231 include/linux/rbtree.h

   212	
   213	/**
   214	 * rb_find_add() - find equivalent @node in @tree, or add @node
   215	 * @node: node to look-for / insert
   216	 * @tree: tree to search / modify
   217	 * @cmp: operator defining the node order
   218	 *
   219	 * Returns the rb_node matching @node, or NULL when no match is found and @node
   220	 * is inserted.
   221	 */
   222	static __always_inline struct rb_node *
   223	rb_find_add(struct rb_node *node, struct rb_root *tree,
   224		    int (*cmp)(struct rb_node *, const struct rb_node *))
   225	{
   226		struct rb_node **link = &tree->rb_node;
   227		struct rb_node *parent = NULL;
   228	
   229		while (*link) {
   230			parent = *link;
 > 231			int c = cmp(node, parent);
   232	
   233			if (c < 0)
   234				link = &parent->rb_left;
   235			else if (c > 0)
   236				link = &parent->rb_right;
   237			else
   238				return parent;
   239		}
   240	
   241		rb_link_node(node, parent, link);
   242		rb_insert_color(node, tree);
   243		return NULL;
   244	}
   245	

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https://github.com/intel/lkp-tests