From: Yu Zhao Date: Fri, 30 Nov 2018 22:09:03 +0000 (-0800) Subject: mm: use swp_offset as key in shmem_replace_page() X-Git-Tag: v4.20-rc5~7^2~26 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c1cb20d43728aa9b5393bd8d489bc85c142949b2;p=thirdparty%2Flinux.git mm: use swp_offset as key in shmem_replace_page() 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-yuzhao@google.com Fixes: f6ab1f7f6b2d ("mm, swap: use offset of swap entry as key of swap cache") Signed-off-by: Yu Zhao Reviewed-by: Matthew Wilcox Acked-by: Hugh Dickins Cc: [4.9+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/shmem.c b/mm/shmem.c index d44991ea5ed4b..42b70978e8148 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1509,11 +1509,13 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp, { 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); /* @@ -1532,7 +1534,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp, __SetPageLocked(newpage); __SetPageSwapBacked(newpage); SetPageUptodate(newpage); - set_page_private(newpage, swap_index); + set_page_private(newpage, entry.val); SetPageSwapCache(newpage); /*