mm/rmap.c: fix pgoff calculation to handle hugepage correctly
I triggered VM_BUG_ON() in vma_address() when I tried to migrate an
anonymous hugepage with mbind() in the kernel v3.16-rc3. This is
because pgoff's calculation in rmap_walk_anon() fails to consider
compound_order() only to have an incorrect value.
This patch introduces page_to_pgoff(), which gets the page's offset in
PAGE_CACHE_SIZE.
Kirill pointed out that page cache tree should natively handle
hugepages, and in order to make hugetlbfs fit it, page->index of
hugetlbfs page should be in PAGE_CACHE_SIZE. This is beyond this patch,
but page_to_pgoff() contains the point to be fixed in a single function.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index c6399e3..7211a73 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -435,7 +435,7 @@
if (av == NULL) /* Not actually mapped anymore */
return;
- pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
+ pgoff = page_to_pgoff(page);
read_lock(&tasklist_lock);
for_each_process (tsk) {
struct anon_vma_chain *vmac;
@@ -469,7 +469,7 @@
mutex_lock(&mapping->i_mmap_mutex);
read_lock(&tasklist_lock);
for_each_process(tsk) {
- pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
+ pgoff_t pgoff = page_to_pgoff(page);
struct task_struct *t = task_early_kill(tsk, force_early);
if (!t)
