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From:   Liu Shixin <liushixin2@huawei.com>
To:     Seth Jennings <sjenning@redhat.com>,
        Dan Streetman <ddstreet@ieee.org>,
        Vitaly Wool <vitaly.wool@konsulko.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Nathan Chancellor <nathan@kernel.org>,
        "Christoph Hellwig" <hch@lst.de>
CC:     <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        Liu Shixin <liushixin2@huawei.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: [PATCH v5 5/5] mm/zswap: skip confusing print info
Date:   Thu, 15 Sep 2022 11:50:03 +0800
Message-ID: <20220915035003.3347466-6-liushixin2@huawei.com>
In-Reply-To: <20220915035003.3347466-1-liushixin2@huawei.com>
References: <20220915035003.3347466-1-liushixin2@huawei.com>
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Precedence: bulk

It's confusing when we disable zswap while zswap is init failed or has no
pool. If no change required, just return directly.

Signed-off-by: Liu Shixin <liushixin2@huawei.com>
---
 mm/zswap.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/mm/zswap.c b/mm/zswap.c
index 4c476c463035..ef7463550e49 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -886,6 +886,15 @@ static int zswap_zpool_param_set(const char *val,
 static int zswap_enabled_param_set(const char *val,
 				   const struct kernel_param *kp)
 {
+	bool res;
+
+	if (kstrtobool(val, &res))
+		return -EINVAL;
+
+	/* no change required */
+	if (res == *(bool *)kp->arg)
+		return 0;
+
 	if (system_state == SYSTEM_RUNNING) {
 		mutex_lock(&zswap_init_lock);
 		if (zswap_setup()) {
-- 
2.25.1