mm/huge_memory: rename freeze_page() to unmap_page()

The term "freeze" is used in several ways in the kernel, and in mm it
has the particular meaning of forcing page refcount temporarily to 0.
freeze_page() is just too confusing a name for a function that unmaps a
page: rename it unmap_page(), and rename unfreeze_page() remap_page().

Went to change the mention of freeze_page() added later in mm/rmap.c,
but found it to be incorrect: ordinary page reclaim reaches there too;
but the substance of the comment still seems correct, so edit it down.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261514080.2275@eggly.anvils
Fixes: e9b61f19858a5 ("thp: reintroduce split_huge_page()")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>	[4.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 10 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index 1e79fac3186b..85b7f9423352 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1627,16 +1627,9 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
                                                       address + PAGE_SIZE);
                 } else {
                         /*
-                         * We should not need to notify here as we reach this
-                         * case only from freeze_page() itself only call from
-                         * split_huge_page_to_list() so everything below must
-                         * be true:
-                         *   - page is not anonymous
-                         *   - page is locked
-                         *
-                         * So as it is a locked file back page thus it can not
-                         * be remove from the page cache and replace by a new
-                         * page before mmu_notifier_invalidate_range_end so no
+                         * This is a locked file-backed page, thus it cannot
+                         * be removed from the page cache and replaced by a new
+                         * page before mmu_notifier_invalidate_range_end, so no
                          * concurrent thread might update its page table to
                          * point at new page while a device still is using this
                          * page.