From: David Hildenbrand <david@redhat.com>
Subject: mm/rmap: pass rmap flags to hugepage_add_anon_rmap()

Let's prepare for passing RMAP_EXCLUSIVE, similarly as we do for
page_add_anon_rmap() now.  RMAP_COMPOUND is implicit for hugetlb pages and
ignored.

Link: https://lkml.kernel.org/r/20220329160440.193848-8-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/rmap.h |    2 +-
 mm/migrate.c         |    3 ++-
 mm/rmap.c            |    9 ++++++---
 3 files changed, 9 insertions(+), 5 deletions(-)

--- a/include/linux/rmap.h~mm-rmap-pass-rmap-flags-to-hugepage_add_anon_rmap
+++ a/include/linux/rmap.h
@@ -191,7 +191,7 @@ void page_add_file_rmap(struct page *, s
 void page_remove_rmap(struct page *, struct vm_area_struct *,
 		bool compound);
 void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *,
-		unsigned long address);
+		unsigned long address, rmap_t flags);
 void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *,
 		unsigned long address);
 
--- a/mm/migrate.c~mm-rmap-pass-rmap-flags-to-hugepage_add_anon_rmap
+++ a/mm/migrate.c
@@ -232,7 +232,8 @@ static bool remove_migration_pte(struct
 			pte = pte_mkhuge(pte);
 			pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
 			if (folio_test_anon(folio))
-				hugepage_add_anon_rmap(new, vma, pvmw.address);
+				hugepage_add_anon_rmap(new, vma, pvmw.address,
+						       RMAP_NONE);
 			else
 				page_dup_file_rmap(new, true);
 			set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte);
--- a/mm/rmap.c~mm-rmap-pass-rmap-flags-to-hugepage_add_anon_rmap
+++ a/mm/rmap.c
@@ -2347,9 +2347,11 @@ void rmap_walk_locked(struct folio *foli
  * The following two functions are for anonymous (private mapped) hugepages.
  * Unlike common anonymous pages, anonymous hugepages have no accounting code
  * and no lru code, because we handle hugepages differently from common pages.
+ *
+ * RMAP_COMPOUND is ignored.
  */
-void hugepage_add_anon_rmap(struct page *page,
-			    struct vm_area_struct *vma, unsigned long address)
+void hugepage_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
+			    unsigned long address, rmap_t flags)
 {
 	struct anon_vma *anon_vma = vma->anon_vma;
 	int first;
@@ -2359,7 +2361,8 @@ void hugepage_add_anon_rmap(struct page
 	/* address might be in next vma when migration races vma_adjust */
 	first = atomic_inc_and_test(compound_mapcount_ptr(page));
 	if (first)
-		__page_set_anon_rmap(page, vma, address, 0);
+		__page_set_anon_rmap(page, vma, address,
+				     !!(flags & RMAP_EXCLUSIVE));
 }
 
 void hugepage_add_new_anon_rmap(struct page *page,
_