sys_swapon: use vzalloc() instead of vmalloc/memset
This patch series refactors the sys_swapon function.
sys_swapon is currently a very large function, with 313 lines (more than
12 25-line screens), which can make it a bit hard to read. This patch
series reduces this size by half, by extracting large chunks of related
code to new helper functions.
One of these chunks of code was nearly identical to the part of
sys_swapoff which is used in case of a failure return from
try_to_unuse(), so this patch series also makes both share the same
code.
As a side effect of all this refactoring, the compiled code gets a bit
smaller (from v1 of this patch series):
text data bss dec hex filename
14012 944 276 15232 3b80 mm/swapfile.o.before
13941 944 276 15161 3b39 mm/swapfile.o.after
This patch:
Use vzalloc() instead of vmalloc/memset.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 6d6d28c..99eb5048 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2047,13 +2047,12 @@
goto bad_swap;
/* OK, set up the swap map and apply the bad block list */
- swap_map = vmalloc(maxpages);
+ swap_map = vzalloc(maxpages);
if (!swap_map) {
error = -ENOMEM;
goto bad_swap;
}
- memset(swap_map, 0, maxpages);
nr_good_pages = maxpages - 1; /* omit header page */
for (i = 0; i < swap_header->info.nr_badpages; i++) {