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mm: convert __do_fault() to use a folio

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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: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2023-11-08 18:28:05 +00:00 committed by Andrew Morton
parent 1e12cbb9f6
commit 01d1e0e6b7
1 changed files with 10 additions and 10 deletions
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20
mm/memory.c
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@ -4245,6 +4245,7 @@ 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;
/*
@ -4273,27 +4274,26 @@ static vm_fault_t __do_fault(struct vm_fault *vmf)
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;
}