[PATCH][V3] net: dsa: sja1105: fix check on while loop exit

[PATCH][V3] net: dsa: sja1105: fix check on while loop exit

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

The while-loop exit condition check is not correct; the
loop should continue if the returns from the function calls are
negative or the CRC status returns are invalid.  Currently it
is ignoring the returns from the function calls.  Fix this by
removing the status return checks and only break from the loop
at the very end when we know that all the success condtions have
been met.

Kudos to Dan Carpenter for describing the correct fix and
Vladimir Oltean for noting the change to the check on the number
of retries.

Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: 8aa9ebccae87 ("net: dsa: Introduce driver for NXP SJA1105 5-port L2 switch")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Tested-by: Vladimir Oltean <olteanv@gmail.com>
---

V2: Discard my broken origina fix. Use correct fix as described by
    Dan Carpenter.
V3: Remove empty line and check for retries != RETRIES fix.
---
 drivers/net/dsa/sja1105/sja1105_spi.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/sja1105/sja1105_spi.c b/drivers/net/dsa/sja1105/sja1105_spi.c
index 244a94ccfc18..49c5252a8dc6 100644
--- a/drivers/net/dsa/sja1105/sja1105_spi.c
+++ b/drivers/net/dsa/sja1105/sja1105_spi.c
@@ -466,14 +466,15 @@ int sja1105_static_config_upload(struct sja1105_private *priv)
 				"invalid, retrying...\n");
 			continue;
 		}
-	} while (--retries && (status.crcchkl == 1 || status.crcchkg == 1 ||
-		 status.configs == 0 || status.ids == 1));
+		/* Success! */
+		break;
+	} while (--retries);
 
 	if (!retries) {
 		rc = -EIO;
 		dev_err(dev, "Failed to upload config to device, giving up\n");
 		goto out;
-	} else if (retries != RETRIES - 1) {
+	} else if (retries != RETRIES) {
 		dev_info(dev, "Succeeded after %d tried\n", RETRIES - retries);
 	}
 
-- 
2.20.1

Re: [PATCH][V3] net: dsa: sja1105: fix check on while loop exit

[David Miller]

From: Colin King <colin.king@canonical.com>
Date: Wed,  8 May 2019 14:30:41 +0100

> From: Colin Ian King <colin.king@canonical.com>
> 
> The while-loop exit condition check is not correct; the
> loop should continue if the returns from the function calls are
> negative or the CRC status returns are invalid.  Currently it
> is ignoring the returns from the function calls.  Fix this by
> removing the status return checks and only break from the loop
> at the very end when we know that all the success condtions have
> been met.
> 
> Kudos to Dan Carpenter for describing the correct fix and
> Vladimir Oltean for noting the change to the check on the number
> of retries.
> 
> Addresses-Coverity: ("Uninitialized scalar variable")
> Fixes: 8aa9ebccae87 ("net: dsa: Introduce driver for NXP SJA1105 5-port L2 switch")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> Tested-by: Vladimir Oltean <olteanv@gmail.com>

Applied, thank you.