From aa8aa8a331d27fcef3e60dabb918eb8c5c9a2ad9 Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Fri, 26 Oct 2018 15:10:55 -0700 Subject: [PATCH 1/1] mm: export add_swap_extent() Btrfs currently does not support swap files because swap's use of bmap does not work with copy-on-write and multiple devices. See 35054394c4b3 ("Btrfs: stop providing a bmap operation to avoid swapfile corruptions"). However, the swap code has a mechanism for the filesystem to manually add swap extents using add_swap_extent() from the ->swap_activate() aop. iomap has done this since 67482129cdab ("iomap: add a swapfile activation function"). Btrfs will do the same in a later patch, so export add_swap_extent(). Link: http://lkml.kernel.org/r/bb1208575e02829aae51b538709476964f97b1ea.1536704650.git.osandov@fb.com Signed-off-by: Omar Sandoval Reviewed-by: Andrew Morton Cc: David Sterba Cc: Johannes Weiner Cc: Nikolay Borisov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/swapfile.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/swapfile.c b/mm/swapfile.c index f0c7e4c11bab..644f746e167a 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2354,6 +2354,7 @@ add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, list_add_tail(&new_se->list, &sis->first_swap_extent.list); return 1; } +EXPORT_SYMBOL_GPL(add_swap_extent); /* * A `swap extent' is a simple thing which maps a contiguous range of pages -- 2.34.1