mm/zpool: use prefixed module loading

mm/zpool: use prefixed module loading

To avoid potential format string expansion via module parameters, do not
use the zpool type directly in request_module() without a format string.
Additionally, to avoid arbitrary modules being loaded via zpool API
(e.g.  via the zswap_zpool_type module parameter) add a "zpool-" prefix
to the requested module, as well as module aliases for the existing
zpool types (zbud and zsmalloc).

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Acked-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 137f8cff505ace6251dc442c7aa973d60c801a79)
Signed-off-by: Alex Shi <alex.shi@linaro.org>
 Conflicts:
	mm/zbud.c

 Conflicts solution:
	remove zbud