+ mm-convert-__do_fault-to-use-a-folio.patch added to mm-hotfixes-unstable branch

+ mm-convert-__do_fault-to-use-a-folio.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

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/mm-convert-__do_fault-to-use-a-folio.patch

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