linux-kernel - [PATCH v1 2/2] zsmalloc: remove unnecessary size

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 11 Aug 2022 18:37:55 +0300
From:   Alexey Romanov <avromanov@...rdevices.ru>
To:     <minchan@...nel.org>, <senozhatsky@...omium.org>,
        <ngupta@...are.org>, <akpm@...ux-foundation.org>
CC:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <kernel@...rdevices.ru>, Alexey Romanov <avromanov@...rdevices.ru>
Subject: [PATCH v1 2/2] zsmalloc: remove unnecessary size_class NULL check

pool->size_class array elements can't be NULL, so this check
is not needed.

In the whole code, we assign pool->size_class[i] values that are
not NULL. Releasing memory for these values occurs in the
zs_destroy_pool() function, which also releases and destroys the pool.

In addition, in the zs_stats_size_show() and async_free_zspage(),
with similar iterations over the array, we don't check it for NULL
pointer.

Signed-off-by: Alexey Romanov <avromanov@...rdevices.ru>
---
 mm/zsmalloc.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 5efa8c592193..f3cf0d0925a3 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -2154,8 +2154,6 @@ unsigned long zs_compact(struct zs_pool *pool)
 
 	for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
 		class = pool->size_class[i];
-		if (!class)
-			continue;
 		if (class->index != i)
 			continue;
 		pages_freed += __zs_compact(pool, class);
@@ -2200,8 +2198,6 @@ static unsigned long zs_shrinker_count(struct shrinker *shrinker,
 
 	for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
 		class = pool->size_class[i];
-		if (!class)
-			continue;
 		if (class->index != i)
 			continue;
 
@@ -2361,9 +2357,6 @@ void zs_destroy_pool(struct zs_pool *pool)
 		int fg;
 		struct size_class *class = pool->size_class[i];
 
-		if (!class)
-			continue;
-
 		if (class->index != i)
 			continue;
 
-- 
2.30.1