4.19-stable review patch. If anyone has any objections, please let me know.
------------------ From: Yu Zhao <yuz...@google.com> commit c1cb20d43728aa9b5393bd8d489bc85c142949b2 upstream. We changed the key of swap cache tree from swp_entry_t.val to swp_offset. We need to do so in shmem_replace_page() as well. Hugh said: "shmem_replace_page() has been wrong since the day I wrote it: good enough to work on swap "type" 0, which is all most people ever use (especially those few who need shmem_replace_page() at all), but broken once there are any non-0 swp_type bits set in the higher order bits" Link: http://lkml.kernel.org/r/20181121215442.138545-1-yuz...@google.com Fixes: f6ab1f7f6b2d ("mm, swap: use offset of swap entry as key of swap cache") Signed-off-by: Yu Zhao <yuz...@google.com> Reviewed-by: Matthew Wilcox <wi...@infradead.org> Acked-by: Hugh Dickins <hu...@google.com> Cc: <sta...@vger.kernel.org> [4.9+] Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- mm/shmem.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1551,11 +1551,13 @@ static int shmem_replace_page(struct pag { struct page *oldpage, *newpage; struct address_space *swap_mapping; + swp_entry_t entry; pgoff_t swap_index; int error; oldpage = *pagep; - swap_index = page_private(oldpage); + entry.val = page_private(oldpage); + swap_index = swp_offset(entry); swap_mapping = page_mapping(oldpage); /* @@ -1574,7 +1576,7 @@ static int shmem_replace_page(struct pag __SetPageLocked(newpage); __SetPageSwapBacked(newpage); SetPageUptodate(newpage); - set_page_private(newpage, swap_index); + set_page_private(newpage, entry.val); SetPageSwapCache(newpage); /*
