drivers/gpu/drm/drm_pagemap.c:480:12: error: call to '__compiletime_assert_473' declared with 'error' attribute: BUILD_BUG failed

:::::: 
:::::: Manual check reason: "__compiletime_assert_NNN"
:::::: 

BCC: [email protected]
CC: [email protected]
CC: [email protected]
TO: Matthew Brost <[email protected]>
CC: Francois Dugast <[email protected]>
CC: Balbir Singh <[email protected]>

Hi Matthew,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   848acc8ffe1b7cd5f1bf427b93069becfebc2c9d
commit: 139ab31aea8a9436460568d556b432bb7e9311f7 drm/pagemap: Correct cpages calculation for migrate_vma_setup
date:   5 months ago
:::::: branch date: 13 hours ago
:::::: commit date: 5 months ago
config: powerpc64-randconfig-r112-20260804 (https://download.01.org/0day-ci/archive/20260804/[email protected]/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
sparse: v0.6.5-rc1
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260804/[email protected]/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
| Fixes: 139ab31aea8a ("drm/pagemap: Correct cpages calculation for migrate_vma_setup")
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/r/[email protected]/

All errors (new ones prefixed by >>):

>> drivers/gpu/drm/drm_pagemap.c:480:12: error: call to '__compiletime_assert_473' declared with 'error' attribute: BUILD_BUG failed
     480 |                         order = HPAGE_PMD_ORDER;
         |                                 ^
   include/linux/huge_mm.h:117:26: note: expanded from macro 'HPAGE_PMD_ORDER'
     117 | #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
         |                          ^
   include/linux/huge_mm.h:113:28: note: expanded from macro 'HPAGE_PMD_SHIFT'
     113 | #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
         |                            ^
   include/linux/build_bug.h:59:21: note: expanded from macro 'BUILD_BUG'
      59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
         |                     ^
   note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   include/linux/compiler_types.h:694:2: note: expanded from macro '_compiletime_assert'
     694 |         __compiletime_assert(condition, msg, prefix, suffix)
         |         ^
   include/linux/compiler_types.h:687:4: note: expanded from macro '__compiletime_assert'
     687 |                         prefix ## suffix();                             \
         |                         ^
   <scratch space>:67:1: note: expanded from here
      67 | __compiletime_assert_473
         | ^
   1 error generated.


vim +480 drivers/gpu/drm/drm_pagemap.c

ec265e1f1cfcce Thomas Hellström 2025-12-19  454  
139ab31aea8a94 Matthew Brost    2026-03-12  455  /**
139ab31aea8a94 Matthew Brost    2026-03-12  456   * drm_pagemap_cpages() - Count collected pages
139ab31aea8a94 Matthew Brost    2026-03-12  457   * @migrate_pfn: Array of migrate_pfn entries to account
139ab31aea8a94 Matthew Brost    2026-03-12  458   * @npages: Number of entries in @migrate_pfn
139ab31aea8a94 Matthew Brost    2026-03-12  459   *
139ab31aea8a94 Matthew Brost    2026-03-12  460   * Compute the total number of minimum-sized pages represented by the
139ab31aea8a94 Matthew Brost    2026-03-12  461   * collected entries in @migrate_pfn. The total is derived from the
139ab31aea8a94 Matthew Brost    2026-03-12  462   * order encoded in each entry.
139ab31aea8a94 Matthew Brost    2026-03-12  463   *
139ab31aea8a94 Matthew Brost    2026-03-12  464   * Return: Total number of minimum-sized pages.
139ab31aea8a94 Matthew Brost    2026-03-12  465   */
139ab31aea8a94 Matthew Brost    2026-03-12  466  static int drm_pagemap_cpages(unsigned long *migrate_pfn, unsigned long npages)
139ab31aea8a94 Matthew Brost    2026-03-12  467  {
139ab31aea8a94 Matthew Brost    2026-03-12  468  	unsigned long i, cpages = 0;
139ab31aea8a94 Matthew Brost    2026-03-12  469  
139ab31aea8a94 Matthew Brost    2026-03-12  470  	for (i = 0; i < npages;) {
139ab31aea8a94 Matthew Brost    2026-03-12  471  		struct page *page = migrate_pfn_to_page(migrate_pfn[i]);
139ab31aea8a94 Matthew Brost    2026-03-12  472  		struct folio *folio;
139ab31aea8a94 Matthew Brost    2026-03-12  473  		unsigned int order = 0;
139ab31aea8a94 Matthew Brost    2026-03-12  474  
139ab31aea8a94 Matthew Brost    2026-03-12  475  		if (page) {
139ab31aea8a94 Matthew Brost    2026-03-12  476  			folio = page_folio(page);
139ab31aea8a94 Matthew Brost    2026-03-12  477  			order = folio_order(folio);
139ab31aea8a94 Matthew Brost    2026-03-12  478  			cpages += NR_PAGES(order);
139ab31aea8a94 Matthew Brost    2026-03-12  479  		} else if (migrate_pfn[i] & MIGRATE_PFN_COMPOUND) {
139ab31aea8a94 Matthew Brost    2026-03-12 @480  			order = HPAGE_PMD_ORDER;
139ab31aea8a94 Matthew Brost    2026-03-12  481  			cpages += NR_PAGES(order);
139ab31aea8a94 Matthew Brost    2026-03-12  482  		}
139ab31aea8a94 Matthew Brost    2026-03-12  483  
139ab31aea8a94 Matthew Brost    2026-03-12  484  		i += NR_PAGES(order);
139ab31aea8a94 Matthew Brost    2026-03-12  485  	}
139ab31aea8a94 Matthew Brost    2026-03-12  486  
139ab31aea8a94 Matthew Brost    2026-03-12  487  	return cpages;
139ab31aea8a94 Matthew Brost    2026-03-12  488  }
139ab31aea8a94 Matthew Brost    2026-03-12  489  

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