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From:   ZhaoLong Wang <wangzhaolong1@huawei.com>
To:     <miquel.raynal@bootlin.com>, <richard@nod.at>, <vigneshr@ti.com>
CC:     <linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <chengzhihao1@huawei.com>, <wangzhaolong1@huawei.com>,
        <yi.zhang@huawei.com>, <yangerkun@huawei.com>
Subject: [PATCH -next] mtd: Add WARN_ON_ONCE() to mtd_read() to check the return value
Date:   Tue, 26 Sep 2023 14:57:33 +0800
Message-ID: <20230926065733.3240322-1-wangzhaolong1@huawei.com>
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If the driver cannot read all the requested data, -EBADMSG or
-EUCLEAN should never be returned.

Add a WARN_ON_ONCE() to help driver developers detect this error.

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
---
 drivers/mtd/mtdcore.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 9bd661be3ae9..848ca4ae058d 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -1505,6 +1505,8 @@ int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 	ret = mtd_read_oob(mtd, from, &ops);
 	*retlen = ops.retlen;
 
+	WARN_ON_ONCE(*retlen != len && mtd_is_bitflip_or_eccerr(ret));
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(mtd_read);
-- 
2.31.1