diff mbox series

[net,1/2] of: of_mdio: Correct loop scanning logic

Message ID 20200619044759.11387-2-f.fainelli@gmail.com
State Superseded
Headers show
Series net: phy: MDIO bus scanning fixes | expand

Checks

Context Check Description
robh/checkpatch warning total: 0 errors, 2 warnings, 12 lines checked

Commit Message

Florian Fainelli June 19, 2020, 4:47 a.m. UTC
Commit 209c65b61d94 ("drivers/of/of_mdio.c:fix of_mdiobus_register()")
introduced a break of the loop on the premise that a successful
registration should exit the loop. The premise is correct but not to
code, because rc && rc != -ENODEV is just a special error condition,
that means we would exit the loop even with rc == -ENODEV which is
absolutely not correct since this is the error code to indicate to the
MDIO bus layer that scanning should continue.

Fix this by explicitly checking for rc = 0 as the only valid condition
to break out of the loop.

Fixes: 209c65b61d94 ("drivers/of/of_mdio.c:fix of_mdiobus_register()")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/of/of_mdio.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Andrew Lunn June 19, 2020, 1:21 p.m. UTC | #1
On Thu, Jun 18, 2020 at 09:47:58PM -0700, Florian Fainelli wrote:
> Commit 209c65b61d94 ("drivers/of/of_mdio.c:fix of_mdiobus_register()")
> introduced a break of the loop on the premise that a successful
> registration should exit the loop. The premise is correct but not to
> code, because rc && rc != -ENODEV is just a special error condition,
> that means we would exit the loop even with rc == -ENODEV which is
> absolutely not correct since this is the error code to indicate to the
> MDIO bus layer that scanning should continue.
> 
> Fix this by explicitly checking for rc = 0 as the only valid condition
> to break out of the loop.
> 
> Fixes: 209c65b61d94 ("drivers/of/of_mdio.c:fix of_mdiobus_register()")
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
>  drivers/of/of_mdio.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
> index a04afe79529c..7496dc64d6b5 100644
> --- a/drivers/of/of_mdio.c
> +++ b/drivers/of/of_mdio.c
> @@ -315,9 +315,10 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
>  
>  			if (of_mdiobus_child_is_phy(child)) {
>  				rc = of_mdiobus_register_phy(mdio, child, addr);
> -				if (rc && rc != -ENODEV)
> +				if (!rc)
> +					break;

Maybe add in a comment here about what ENODEV means in this context?
That might avoid it getting broken again in the future.

> +				if (rc != -ENODEV)
>  					goto unregister;
> -				break;
>  			}
>  		}
>  	}
> -- 

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew
diff mbox series

Patch

diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index a04afe79529c..7496dc64d6b5 100644
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -315,9 +315,10 @@  int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
 
 			if (of_mdiobus_child_is_phy(child)) {
 				rc = of_mdiobus_register_phy(mdio, child, addr);
-				if (rc && rc != -ENODEV)
+				if (!rc)
+					break;
+				if (rc != -ENODEV)
 					goto unregister;
-				break;
 			}
 		}
 	}