mm: page_vma_mapped_walk(): use page for pvmw->page

Patch series "mm: page_vma_mapped_walk() cleanup and THP fixes".

I've marked all of these for stable: many are merely cleanups, but I
think they are much better before the main fix than after.

This patch (of 11):

page_vma_mapped_walk() cleanup: sometimes the local copy of pvwm->page
was used, sometimes pvmw->page itself: use the local copy "page"
throughout.

Link: https://lkml.kernel.org/r/589b358c-febc-c88e-d4c2-7834b37fa7bf@google.com
Link: https://lkml.kernel.org/r/88e67645-f467-c279-bf5e-af4b5c6b13eb@google.comSigned-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_vma_mapped.c

@@ -156,7 +156,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
 	if (pvmw->pte)
 		goto next_pte;
 
-	if (unlikely(PageHuge(pvmw->page))) {
+	if (unlikely(PageHuge(page))) {
 		/* when pud is not present, pte will be NULL */
 		pvmw->pte = huge_pte_offset(mm, pvmw->address, page_size(page));
 		if (!pvmw->pte)
@@ -217,8 +217,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
 		 * cannot return prematurely, while zap_huge_pmd() has
 		 * cleared *pmd but not decremented compound_mapcount().
 		 */
-		if ((pvmw->flags & PVMW_SYNC) &&
-		    PageTransCompound(pvmw->page)) {
+		if ((pvmw->flags & PVMW_SYNC) && PageTransCompound(page)) {
 			spinlock_t *ptl = pmd_lock(mm, pvmw->pmd);
 
 			spin_unlock(ptl);
@@ -234,9 +233,9 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
 			return true;
 next_pte:
 		/* Seek to next pte only makes sense for THP */
-		if (!PageTransHuge(pvmw->page) || PageHuge(pvmw->page))
+		if (!PageTransHuge(page) || PageHuge(page))
 			return not_found(pvmw);
-		end = vma_address_end(pvmw->page, pvmw->vma);
+		end = vma_address_end(page, pvmw->vma);
 		do {
 			pvmw->address += PAGE_SIZE;
 			if (pvmw->address >= end)