mm: export add_swap_extent()
authorOmar Sandoval <osandov@fb.com>
Fri, 26 Oct 2018 22:10:55 +0000 (15:10 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 26 Oct 2018 23:38:15 +0000 (16:38 -0700)
commitaa8aa8a331d27fcef3e60dabb918eb8c5c9a2ad9
tree5f200509a0bcf548126fc9abe385637924555853
parentbc4ae27d817a4e92071ef67cb6368120cfabe7ec
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 <osandov@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Sterba <dsterba@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/swapfile.c