[gourryinverse:scratch/gourry/managed_nodes/n_memory_features 38/58] mm/page_alloc.c:4804 check_retry_private() warn: bitwise AND condition is false here

[gourryinverse:scratch/gourry/managed_nodes/n_memory_features 38/58] mm/page_alloc.c:4804 check_retry_private() warn: bitwise AND condition is false here

[kernel test robot]

Unfiltered warning: this smatch report is sent as-is and has not been
reviewed for false positives, so please treat it with due skepticism.

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
CC: Gregory Price <gourry@gourry.net>
TO: "Gregory Price (Meta)" <gourry@gourry.net>

tree:   https://github.com/gourryinverse/linux scratch/gourry/managed_nodes/n_memory_features
head:   82ebacf36393992b1a30dcbf1826f73f6bc34f1d
commit: 61ca25fef1e1cd792c1fd8328734121c5347afd0 [38/58] mm/page_alloc: return to common zonelists when relaxing a mask
:::::: branch date: 12 hours ago
:::::: commit date: 12 hours ago
config: mips-randconfig-2200-20261114 (https://download.01.org/0day-ci/archive/20261114/202611141203.DgUJcomz-lkp@intel.com/config)
compiler: mips64-linux-gcc (GCC) 15.3.0
smatch: v0.5.0-9187-g5189e3fb

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@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202611141203.DgUJcomz-lkp@intel.com/

smatch warnings:
mm/page_alloc.c:4804 check_retry_private() warn: bitwise AND condition is false here

vim +4804 mm/page_alloc.c

902b62810a57ba Vlastimil Babka      2017-07-06  4793  
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4794) /*
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4795)  * A private request stays strict while its zonelist holds an allowed node.
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4796)  * Recheck the cpuset and zonelist cookies before relaxing it to common memory.
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4797)  */
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4798) static bool check_retry_private(gfp_t gfp, int cpuset_mems_cookie,
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4799) 				unsigned int zonelist_iter_cookie,
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4800) 				struct alloc_context *ac)
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4801) {
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4802) 	/* A strict local private request keeps its allocation domain. */
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4803) 	bool policy_valid = ((gfp & __GFP_THISNODE) &&
61ca25fef1e1cd Gregory Price (Meta  2026-10-13 @4804) 			     (ac->alloc_flags & ALLOC_ZONELIST_PRIVATE)) ||
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4805) 			    alloc_policy_valid(ac);
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4806) 
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4807) 	if (read_mems_allowed_retry(cpuset_mems_cookie) ||
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4808) 	    check_retry_zonelist(zonelist_iter_cookie))
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4809) 		return true;
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4810) 	if (policy_valid)
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4811) 		return false;
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4812) 
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4813) 	ac->nodemask = NULL;
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4814) 	ac->alloc_flags &= ~ALLOC_ZONELIST_PRIVATE;
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4815) 	ac->zonelist = node_zonelist(ac->preferred_nid, gfp);
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4816) 	return true;
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4817) }
61ca25fef1e1cd Gregory Price (Meta  2026-10-13  4818) 

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