[PATCH 4.9 106/121] ieee802154/adf7242: check status of adf7242_read_reg

[Greg Kroah-Hartman]

From: Tom Rix <trix@xxxxxxxxxx>

[ Upstream commit e3914ed6cf44bfe1f169e26241f8314556fd1ac1 ]

Clang static analysis reports this error

adf7242.c:887:6: warning: Assigned value is garbage or undefined
        len = len_u8;
            ^ ~~~~~~

len_u8 is set in
       adf7242_read_reg(lp, 0, &len_u8);

When this call fails, len_u8 is not set.

So check the return code.

Fixes: 7302b9d90117 ("ieee802154/adf7242: Driver for ADF7242 MAC IEEE802154")

Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
Acked-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200802142339.21091-1-trix@xxxxxxxxxx
Signed-off-by: Stefan Schmidt <stefan@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/ieee802154/adf7242.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ieee802154/adf7242.c b/drivers/net/ieee802154/adf7242.c
index 1b980f12663af..a605dfb15bb75 100644
--- a/drivers/net/ieee802154/adf7242.c
+++ b/drivers/net/ieee802154/adf7242.c
@@ -834,7 +834,9 @@ static int adf7242_rx(struct adf7242_local *lp)
 	int ret;
 	u8 lqi, len_u8, *data;
 
-	adf7242_read_reg(lp, 0, &len_u8);
+	ret = adf7242_read_reg(lp, 0, &len_u8);
+	if (ret)
+		return ret;
 
 	len = len_u8;
 
-- 
2.25.1