The patch titled Subject: mm: convert __do_fault() to use a folio has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-convert-__do_fault-to-use-a-folio.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: "Matthew Wilcox (Oracle)" willy@infradead.org Subject: mm: convert __do_fault() to use a folio Date: Wed, 8 Nov 2023 18:28:05 +0000

Convert vmf->page to a folio as soon as we're going to use it. This fixes a bug if the fault handler returns a tail page with hardware poison; tail pages have an invalid page->index, so we would fail to unmap the page from the page tables. We actually have to unmap the entire folio (or mapping_evict_folio() will fail), so use unmap_mapping_folio() instead.

This also saves various calls to compound_head() hidden in lock_page(), put_page(), etc.

Link: https://lkml.kernel.org/r/20231108182809.602073-3-willy@infradead.org Fixes: 793917d997df ("mm/readahead: Add large folio readahead") Signed-off-by: Matthew Wilcox (Oracle) willy@infradead.org Cc: stable@vger.kernel.org Cc: Naoya Horiguchi naoya.horiguchi@nec.com Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/memory.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)

--- a/mm/memory.c~mm-convert-__do_fault-to-use-a-folio +++ a/mm/memory.c @@ -4239,6 +4239,7 @@ oom: static vm_fault_t __do_fault(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; + struct folio *folio; vm_fault_t ret;

/* @@ -4267,27 +4268,26 @@ static vm_fault_t __do_fault(struct vm_f VM_FAULT_DONE_COW))) return ret;

+ folio = page_folio(vmf->page); if (unlikely(PageHWPoison(vmf->page))) { - struct page *page = vmf->page; vm_fault_t poisonret = VM_FAULT_HWPOISON; if (ret & VM_FAULT_LOCKED) { - if (page_mapped(page)) - unmap_mapping_pages(page_mapping(page), - page->index, 1, false); - /* Retry if a clean page was removed from the cache. */ - if (invalidate_inode_page(page)) + if (page_mapped(vmf->page)) + unmap_mapping_folio(folio); + /* Retry if a clean folio was removed from the cache. */ + if (mapping_evict_folio(folio->mapping, folio)) poisonret = VM_FAULT_NOPAGE; - unlock_page(page); + folio_unlock(folio); } - put_page(page); + folio_put(folio); vmf->page = NULL; return poisonret; }

if (unlikely(!(ret & VM_FAULT_LOCKED))) - lock_page(vmf->page); + folio_lock(folio); else - VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page); + VM_BUG_ON_PAGE(!folio_test_locked(folio), vmf->page);

return ret; } _

Patches currently in -mm which might be from willy@infradead.org are

mm-make-mapping_evict_folio-the-preferred-way-to-evict-clean-folios.patch mm-convert-__do_fault-to-use-a-folio.patch mm-use-mapping_evict_folio-in-truncate_error_page.patch mm-convert-soft_offline_in_use_page-to-use-a-folio.patch mm-convert-isolate_page-to-mf_isolate_folio.patch mm-remove-invalidate_inode_page.patch