When spi_write_then_read() fails, "data" can be uninitialized and thus
may contain a random value; the following execution checks "data" with a
mask, the result could be random.

The fix inserts a check of spi_write_then_read(): if it fails, always
returns -1.

Signed-off-by: Kangjie Lu <k...@umn.edu>
---
 drivers/net/wan/slic_ds26522.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wan/slic_ds26522.c b/drivers/net/wan/slic_ds26522.c
index 1f6bc8791d51..89681910d875 100644
--- a/drivers/net/wan/slic_ds26522.c
+++ b/drivers/net/wan/slic_ds26522.c
@@ -64,8 +64,9 @@ static u8 slic_read(struct spi_device *spi, u16 addr)
        temp[0] = (u8)(((addr >> 8) & 0x7f) | 0x80);
        temp[1] = (u8)(addr & 0xfe);
 
-       spi_write_then_read(spi, &temp[0], SLIC_TWO_LEN, &data,
-                           SLIC_TRANS_LEN);
+       if (spi_write_then_read(spi, &temp[0], SLIC_TWO_LEN, &data,
+                           SLIC_TRANS_LEN))
+               return -1;
 
        data = bitrev8(data);
        return data;
-- 
2.17.2 (Apple Git-113)

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