Re: [PATCH 03/24] mm/swap: move no readahead swapin code to a stand alone helper

From: Dan Carpenter
Date: Mon Nov 20 2023 - 09:56:20 EST


Hi Kairui,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Kairui-Song/mm-swap-fix-a-potential-undefined-behavior-issue/20231120-035926
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/20231119194740.94101-4-ryncsn%40gmail.com
patch subject: [PATCH 03/24] mm/swap: move no readahead swapin code to a stand alone helper
config: um-randconfig-r081-20231120 (https://download.01.org/0day-ci/archive/20231120/202311201135.iG2KLShW-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce: (https://download.01.org/0day-ci/archive/20231120/202311201135.iG2KLShW-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Reported-by: Dan Carpenter <error27@xxxxxxxxx>
| Closes: https://lore.kernel.org/r/202311201135.iG2KLShW-lkp@xxxxxxxxx/

smatch warnings:
mm/swap_state.c:881 swapin_no_readahead() warn: use 'gfp_mask' here instead of GFP_KERNEL?

vim +/gfp_mask +881 mm/swap_state.c

19f582d2684e47 Kairui Song 2023-11-20 856 /**
19f582d2684e47 Kairui Song 2023-11-20 857 * swapin_no_readahead - swap in pages skipping swap cache and readahead
19f582d2684e47 Kairui Song 2023-11-20 858 * @entry: swap entry of this memory
19f582d2684e47 Kairui Song 2023-11-20 859 * @gfp_mask: memory allocation flags
19f582d2684e47 Kairui Song 2023-11-20 860 * @vmf: fault information
19f582d2684e47 Kairui Song 2023-11-20 861 *
19f582d2684e47 Kairui Song 2023-11-20 862 * Returns the struct page for entry and addr after the swap entry is read
19f582d2684e47 Kairui Song 2023-11-20 863 * in.
19f582d2684e47 Kairui Song 2023-11-20 864 */
19f582d2684e47 Kairui Song 2023-11-20 865 struct page *swapin_no_readahead(swp_entry_t entry, gfp_t gfp_mask,
19f582d2684e47 Kairui Song 2023-11-20 866 struct vm_fault *vmf)
19f582d2684e47 Kairui Song 2023-11-20 867 {
19f582d2684e47 Kairui Song 2023-11-20 868 struct vm_area_struct *vma = vmf->vma;
19f582d2684e47 Kairui Song 2023-11-20 869 struct page *page = NULL;
19f582d2684e47 Kairui Song 2023-11-20 870 struct folio *folio;
19f582d2684e47 Kairui Song 2023-11-20 871 void *shadow = NULL;
19f582d2684e47 Kairui Song 2023-11-20 872
19f582d2684e47 Kairui Song 2023-11-20 873 folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0,
19f582d2684e47 Kairui Song 2023-11-20 874 vma, vmf->address, false);
19f582d2684e47 Kairui Song 2023-11-20 875 if (folio) {
19f582d2684e47 Kairui Song 2023-11-20 876 __folio_set_locked(folio);
19f582d2684e47 Kairui Song 2023-11-20 877 __folio_set_swapbacked(folio);
19f582d2684e47 Kairui Song 2023-11-20 878
19f582d2684e47 Kairui Song 2023-11-20 879 if (mem_cgroup_swapin_charge_folio(folio,
19f582d2684e47 Kairui Song 2023-11-20 880 vma->vm_mm, GFP_KERNEL,

s/GFP_KERNEL/gfp_mask/?

19f582d2684e47 Kairui Song 2023-11-20 @881 entry)) {
19f582d2684e47 Kairui Song 2023-11-20 882 folio_unlock(folio);
19f582d2684e47 Kairui Song 2023-11-20 883 folio_put(folio);
19f582d2684e47 Kairui Song 2023-11-20 884 return NULL;
19f582d2684e47 Kairui Song 2023-11-20 885 }
19f582d2684e47 Kairui Song 2023-11-20 886 mem_cgroup_swapin_uncharge_swap(entry);
19f582d2684e47 Kairui Song 2023-11-20 887
19f582d2684e47 Kairui Song 2023-11-20 888 shadow = get_shadow_from_swap_cache(entry);
19f582d2684e47 Kairui Song 2023-11-20 889 if (shadow)
19f582d2684e47 Kairui Song 2023-11-20 890 workingset_refault(folio, shadow);
19f582d2684e47 Kairui Song 2023-11-20 891
19f582d2684e47 Kairui Song 2023-11-20 892 folio_add_lru(folio);
19f582d2684e47 Kairui Song 2023-11-20 893
19f582d2684e47 Kairui Song 2023-11-20 894 /* To provide entry to swap_readpage() */
19f582d2684e47 Kairui Song 2023-11-20 895 folio->swap = entry;
19f582d2684e47 Kairui Song 2023-11-20 896 page = &folio->page;
19f582d2684e47 Kairui Song 2023-11-20 897 swap_readpage(page, true, NULL);
19f582d2684e47 Kairui Song 2023-11-20 898 folio->private = NULL;
19f582d2684e47 Kairui Song 2023-11-20 899 }
19f582d2684e47 Kairui Song 2023-11-20 900
19f582d2684e47 Kairui Song 2023-11-20 901 return page;
19f582d2684e47 Kairui Song 2023-11-20 902 }

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