diff mbox series

[020/156] mm/memory: remove page fault assumption of compound page size

Message ID 20201016024206.NjQzcrMM8%akpm@linux-foundation.org
State New
Headers show
Series [001/156] device-dax/kmem: fix resource release | expand

Commit Message

Andrew Morton Oct. 16, 2020, 2:42 a.m. UTC
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: mm/memory: remove page fault assumption of compound page size

A compound page in the page cache will not necessarily be of PMD size,
so check explicitly.

[willy@infradead.org: fix remove page fault assumption of compound page size]
  Link: https://lkml.kernel.org/r/20201001152259.14932-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20200908195539.25896-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)
diff mbox series

Patch

--- a/mm/memory.c~mm-memory-remove-page-fault-assumption-of-compound-page-size
+++ a/mm/memory.c
@@ -3709,13 +3709,14 @@  static vm_fault_t do_set_pmd(struct vm_f
 	unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
 	pmd_t entry;
 	int i;
-	vm_fault_t ret;
+	vm_fault_t ret = VM_FAULT_FALLBACK;
 
 	if (!transhuge_vma_suitable(vma, haddr))
-		return VM_FAULT_FALLBACK;
+		return ret;
 
-	ret = VM_FAULT_FALLBACK;
 	page = compound_head(page);
+	if (compound_order(page) != HPAGE_PMD_ORDER)
+		return ret;
 
 	/*
 	 * Archs like ppc64 need additonal space to store information