zcomp: Use ARRAY_SIZE() for backends list

Instead of keeping NULL terminated array switch to use ARRAY_SIZE()
which helps to further clean up.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: http://lkml.kernel.org/r/20200508100758.51644-1-andriy.shevchenko@linux.intel.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/block/zram/zcomp.c

@@ -29,7 +29,6 @@ static const char * const backends[] = {
 #if IS_ENABLED(CONFIG_CRYPTO_ZSTD)
 	"zstd",
 #endif
-	NULL
 };
 
 static void zcomp_strm_free(struct zcomp_strm *zstrm)
@@ -64,7 +63,7 @@ bool zcomp_available_algorithm(const char *comp)
 {
 	int i;
 
-	i = __sysfs_match_string(backends, -1, comp);
+	i = sysfs_match_string(backends, comp);
 	if (i >= 0)
 		return true;
 
@@ -83,9 +82,9 @@ ssize_t zcomp_available_show(const char *comp, char *buf)
 {
 	bool known_algorithm = false;
 	ssize_t sz = 0;
-	int i = 0;
+	int i;
 
-	for (; backends[i]; i++) {
+	for (i = 0; i < ARRAY_SIZE(backends); i++) {
 		if (!strcmp(comp, backends[i])) {
 			known_algorithm = true;
 			sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,