[PATCH 3/4] drm/ttm: Consider hitch moves within bulk sublist moves

[kernel test robot]

Hi Thomas,

kernel test robot noticed the following build warnings:

[auto build test WARNING on drm-misc/drm-misc-next]
[also build test WARNING on drm-tip/drm-tip next-20240216]
[cannot apply to drm-intel/for-linux-next drm-intel/for-linux-next-fixes linus/master v6.8-rc4]
[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/Thomas-Hellstr-m/drm-ttm-Allow-TTM-LRU-list-nodes-of-different-types/20240216-211801
base:   git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
patch link:    https://lore.kernel.org/r/20240216131446.101961-4-thomas.hellstrom%40linux.intel.com
patch subject: [PATCH 3/4] drm/ttm: Consider hitch moves within bulk sublist moves
config: x86_64-randconfig-121-20240217 (https://download.01.org/0day-ci/archive/20240218/202402180043.xVwOJQs2-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240218/202402180043.xVwOJQs2-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202402180043.xVwOJQs2-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/gpu/drm/ttm/ttm_resource.c:545:34: sparse: sparse: incorrect type in assignment (different base types) @@     expected unsigned long long [usertype] bulk_age @@     got unsigned long long * @@
   drivers/gpu/drm/ttm/ttm_resource.c:545:34: sparse:     expected unsigned long long [usertype] bulk_age
   drivers/gpu/drm/ttm/ttm_resource.c:545:34: sparse:     got unsigned long long *
>> drivers/gpu/drm/ttm/ttm_resource.c:551:30: sparse: sparse: incompatible types for operation (==):
   drivers/gpu/drm/ttm/ttm_resource.c:551:30: sparse:    unsigned long long [usertype] bulk_age
   drivers/gpu/drm/ttm/ttm_resource.c:551:30: sparse:    unsigned long long *
   drivers/gpu/drm/ttm/ttm_resource.c: note: in included file (through include/linux/fwnode.h, include/linux/logic_pio.h, include/asm-generic/io.h, ...):
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true

vim +545 drivers/gpu/drm/ttm/ttm_resource.c

   517	
   518	/* Adjust to a bulk sublist being bumped while traversing it.*/
   519	static bool
   520	ttm_resource_cursor_check_bulk(struct ttm_resource_cursor *cursor,
   521				       struct ttm_lru_item *next_lru)
   522	{
   523		struct ttm_resource *next = ttm_lru_item_to_res(next_lru);
   524		struct ttm_lru_bulk_move *bulk = NULL;
   525		struct ttm_buffer_object *bo = next->bo;
   526	
   527		lockdep_assert_held(&cursor->man->bdev->lru_lock);
   528		if (bo && bo->resource == next)
   529			bulk = bo->bulk_move;
   530	
   531		if (!bulk) {
   532			ttm_resource_cursor_clear_bulk(cursor);
   533			return false;
   534		}
   535	
   536		/*
   537		 * We encountered a bulk sublist. Record its age and
   538		 * set a hitch after the sublist.
   539		 */
   540		if (cursor->bulk != bulk) {
   541			struct ttm_lru_bulk_move_pos *pos =
   542				ttm_lru_bulk_move_pos(bulk, next);
   543	
   544			cursor->bulk = bulk;
 > 545			cursor->bulk_age = &bulk->age;
   546			list_move(&cursor->bulk_hitch.link, &pos->last->lru.link);
   547			return false;
   548		}
   549	
   550		/* Continue iterating down the bulk sublist */
 > 551		if (cursor->bulk_age == &bulk->age)
   552			return false;
   553	
   554		/*
   555		 * The bulk sublist in which we had a hitch has moved and the
   556		 * hitch moved with it. Restart iteration from a previously
   557		 * set hitch after the bulk_move, and remove that backup
   558		 * hitch.
   559		 */
   560		list_move(&cursor->hitch.link, &cursor->bulk_hitch.link);
   561		ttm_resource_cursor_clear_bulk(cursor);
   562	
   563		return true;
   564	}
   565	

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