Re: [hnaz-mm:master 214/410] mm/madvise.c:632:8: error: call to undeclared function 'is_swapin_error_entry'; ISO C99 and later do not support implicit function declarations
From: Miaohe Lin
Date: Thu Apr 28 2022 - 06:47:56 EST
On 2022/4/28 15:48, Miaohe Lin wrote:
> On 2022/4/28 14:54, kernel test robot wrote:
>> tree: https://github.com/hnaz/linux-mm master
>> head: bf4803abaa3e9d2fa207c0675a2d2abf0fd44f66
>> commit: fe343091405131f91dcb9230ae7649bb1ee7fe9a [214/410] mm/madvise: free hwpoison and swapin error entry in madvise_free_pte_range
>> config: i386-randconfig-a005-20220425 (https://download.01.org/0day-ci/archive/20220428/202204281452.cEOGcf4p-lkp@xxxxxxxxx/config)
>> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 1cddcfdc3c683b393df1a5c9063252eb60e52818)
>> 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/hnaz/linux-mm/commit/fe343091405131f91dcb9230ae7649bb1ee7fe9a
>> git remote add hnaz-mm https://github.com/hnaz/linux-mm
>> git fetch --no-tags hnaz-mm master
>> git checkout fe343091405131f91dcb9230ae7649bb1ee7fe9a
>> # save the config file
>> mkdir build_dir && cp config build_dir/.config
>> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>>
>> Note: the hnaz-mm/master HEAD bf4803abaa3e9d2fa207c0675a2d2abf0fd44f66 builds fine.
>> It only hurts bisectability.
>>
>> All errors (new ones prefixed by >>):
>>
>>>> mm/madvise.c:632:8: error: call to undeclared function 'is_swapin_error_entry'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>> is_swapin_error_entry(entry)) {
>> ^
>> 1 error generated.
>
> I browsed the config file and found that CONFIG_SWAP is not set. But when I test it on my env, it works.
> And I'm somewhat confused now:
>
> is_swapin_error_entry and pte_to_swp_entry are both defined in include/linux/swapops.h. But pte_to_swp_entry
> can be used normally but is_swapin_error_entry breaks the compile.
>
> Will take a more close look later. Thanks for report!
I'm sorry but I can't reproduce it in my env. It's very kind of you if you can help test the attached patch.
Or should I send this patch directly?
Thanks!
>
>>
>>
>> vim +/is_swapin_error_entry +632 mm/madvise.c
>>
>> 587
>> 588 static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
>> 589 unsigned long end, struct mm_walk *walk)
>> 590
>> 591 {
>> 592 struct mmu_gather *tlb = walk->private;
>> 593 struct mm_struct *mm = tlb->mm;
>> 594 struct vm_area_struct *vma = walk->vma;
>> 595 spinlock_t *ptl;
>> 596 pte_t *orig_pte, *pte, ptent;
>> 597 struct page *page;
>> 598 int nr_swap = 0;
>> 599 unsigned long next;
>> 600
>> 601 next = pmd_addr_end(addr, end);
>> 602 if (pmd_trans_huge(*pmd))
>> 603 if (madvise_free_huge_pmd(tlb, vma, pmd, addr, next))
>> 604 goto next;
>> 605
>> 606 if (pmd_trans_unstable(pmd))
>> 607 return 0;
>> 608
>> 609 tlb_change_page_size(tlb, PAGE_SIZE);
>> 610 orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
>> 611 flush_tlb_batched_pending(mm);
>> 612 arch_enter_lazy_mmu_mode();
>> 613 for (; addr != end; pte++, addr += PAGE_SIZE) {
>> 614 ptent = *pte;
>> 615
>> 616 if (pte_none(ptent))
>> 617 continue;
>> 618 /*
>> 619 * If the pte has swp_entry, just clear page table to
>> 620 * prevent swap-in which is more expensive rather than
>> 621 * (page allocation + zeroing).
>> 622 */
>> 623 if (!pte_present(ptent)) {
>> 624 swp_entry_t entry;
>> 625
>> 626 entry = pte_to_swp_entry(ptent);
>> 627 if (!non_swap_entry(entry)) {
>> 628 nr_swap--;
>> 629 free_swap_and_cache(entry);
>> 630 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
>> 631 } else if (is_hwpoison_entry(entry) ||
>> > 632 is_swapin_error_entry(entry)) {
>> 633 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
>> 634 }
>> 635 continue;
>> 636 }
>> 637
>> 638 page = vm_normal_page(vma, addr, ptent);
>> 639 if (!page)
>> 640 continue;
>> 641
>> 642 /*
>> 643 * If pmd isn't transhuge but the page is THP and
>> 644 * is owned by only this process, split it and
>> 645 * deactivate all pages.
>> 646 */
>> 647 if (PageTransCompound(page)) {
>> 648 if (page_mapcount(page) != 1)
>> 649 goto out;
>> 650 get_page(page);
>> 651 if (!trylock_page(page)) {
>> 652 put_page(page);
>> 653 goto out;
>> 654 }
>> 655 pte_unmap_unlock(orig_pte, ptl);
>> 656 if (split_huge_page(page)) {
>> 657 unlock_page(page);
>> 658 put_page(page);
>> 659 orig_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
>> 660 goto out;
>> 661 }
>> 662 unlock_page(page);
>> 663 put_page(page);
>> 664 orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
>> 665 pte--;
>> 666 addr -= PAGE_SIZE;
>> 667 continue;
>> 668 }
>> 669
>> 670 VM_BUG_ON_PAGE(PageTransCompound(page), page);
>> 671
>> 672 if (PageSwapCache(page) || PageDirty(page)) {
>> 673 if (!trylock_page(page))
>> 674 continue;
>> 675 /*
>> 676 * If page is shared with others, we couldn't clear
>> 677 * PG_dirty of the page.
>> 678 */
>> 679 if (page_mapcount(page) != 1) {
>> 680 unlock_page(page);
>> 681 continue;
>> 682 }
>> 683
>> 684 if (PageSwapCache(page) && !try_to_free_swap(page)) {
>> 685 unlock_page(page);
>> 686 continue;
>> 687 }
>> 688
>> 689 ClearPageDirty(page);
>> 690 unlock_page(page);
>> 691 }
>> 692
>> 693 if (pte_young(ptent) || pte_dirty(ptent)) {
>> 694 /*
>> 695 * Some of architecture(ex, PPC) don't update TLB
>> 696 * with set_pte_at and tlb_remove_tlb_entry so for
>> 697 * the portability, remap the pte with old|clean
>> 698 * after pte clearing.
>> 699 */
>> 700 ptent = ptep_get_and_clear_full(mm, addr, pte,
>> 701 tlb->fullmm);
>> 702
>> 703 ptent = pte_mkold(ptent);
>> 704 ptent = pte_mkclean(ptent);
>> 705 set_pte_at(mm, addr, pte, ptent);
>> 706 tlb_remove_tlb_entry(tlb, pte, addr);
>> 707 }
>> 708 mark_page_lazyfree(page);
>> 709 }
>> 710 out:
>> 711 if (nr_swap) {
>> 712 if (current->mm == mm)
>> 713 sync_mm_rss(mm);
>> 714
>> 715 add_mm_counter(mm, MM_SWAPENTS, nr_swap);
>> 716 }
>> 717 arch_leave_lazy_mmu_mode();
>> 718 pte_unmap_unlock(orig_pte, ptl);
>> 719 cond_resched();
>> 720 next:
>> 721 return 0;
>> 722 }
>> 723
>>
>
From c7b3d6e0a15fd4e85a8f7333abb2220a54c052e5 Mon Sep 17 00:00:00 2001
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Date: Thu, 28 Apr 2022 17:21:55 +0800
Subject: [PATCH] mm/swap: fix implicit function declarations of
is_swapin_error_entry
Kernel test robot reported the error of calling to undeclared function
is_swapin_error_entry. Fix it by wrapping up is_swapin_error_entry with
CONFIG_SWAP.
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
include/linux/swap.h | 4 ++++
include/linux/swapops.h | 7 +++++++
2 files changed, 11 insertions(+)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index b82c196d8867..f3d44252e477 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -55,10 +55,14 @@ static inline int current_is_kswapd(void)
* actions on faults.
*/
+#ifdef CONFIG_SWAP
#define SWP_SWAPIN_ERROR_NUM 1
#define SWP_SWAPIN_ERROR (MAX_SWAPFILES + SWP_HWPOISON_NUM + \
SWP_MIGRATION_NUM + SWP_DEVICE_NUM + \
SWP_PTE_MARKER_NUM)
+#else
+#define SWP_SWAPIN_ERROR_NUM 0
+#endif
/*
* PTE markers are used to persist information onto PTEs that are mapped with
* file-backed memories. As its name "PTE" hints, it should only be applied to
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index ffc9f19ab6fb..af6e6fb4b8e6 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -108,6 +108,7 @@ static inline void *swp_to_radix_entry(swp_entry_t entry)
return xa_mk_value(entry.val);
}
+#ifdef CONFIG_SWAP
static inline swp_entry_t make_swapin_error_entry(struct page *page)
{
return swp_entry(SWP_SWAPIN_ERROR, page_to_pfn(page));
@@ -117,6 +118,12 @@ static inline int is_swapin_error_entry(swp_entry_t entry)
{
return swp_type(entry) == SWP_SWAPIN_ERROR;
}
+#else
+static inline int is_swapin_error_entry(swp_entry_t entry)
+{
+ return 0;
+}
+#endif
#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
--
2.23.0