[Patch net] net: dsa: microchip: ksz9477: fix fdb_dump last invalid entry

[Patch net] net: dsa: microchip: ksz9477: fix fdb_dump last invalid entry

[Arun Ramadoss]

In the ksz9477_fdb_dump function it reads the ALU control register and
exit from the timeout loop if there is valid entry or search is
complete. After exiting the loop, it reads the alu entry and report to
the user space irrespective of entry is valid. It works till the valid
entry. If the loop exited when search is complete, it reads the alu
table. The table returns all ones and it is reported to user space. So
bridge fdb show gives ff:ff:ff:ff:ff:ff as last entry for every port.
To fix it, after exiting the loop the entry is reported only if it is
valid one.

Fixes: c2e866911e25 ("net: dsa: microchip: break KSZ9477 DSA driver into two files")
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
---
 drivers/net/dsa/microchip/ksz9477.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index 4b14d80d27ed..aa961dc03ddf 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -613,15 +613,17 @@ int ksz9477_fdb_dump(struct ksz_device *dev, int port,
 			goto exit;
 		}
 
-		/* read ALU table */
-		ksz9477_read_table(dev, alu_table);
+		if (ksz_data & ALU_VALID) {
+			/* read ALU table */
+			ksz9477_read_table(dev, alu_table);
 
-		ksz9477_convert_alu(&alu, alu_table);
+			ksz9477_convert_alu(&alu, alu_table);
 
-		if (alu.port_forward & BIT(port)) {
-			ret = cb(alu.mac, alu.fid, alu.is_static, data);
-			if (ret)
-				goto exit;
+			if (alu.port_forward & BIT(port)) {
+				ret = cb(alu.mac, alu.fid, alu.is_static, data);
+				if (ret)
+					goto exit;
+			}
 		}
 	} while (ksz_data & ALU_START);
 

base-commit: f86d1fbbe7858884d6754534a0afbb74fc30bc26
-- 
2.36.1

Re: [Patch net] net: dsa: microchip: ksz9477: fix fdb_dump last invalid entry

[Vladimir Oltean]

On Fri, Aug 12, 2022 at 03:04:11PM +0530, Arun Ramadoss wrote:
> In the ksz9477_fdb_dump function it reads the ALU control register and
> exit from the timeout loop if there is valid entry or search is
> complete. After exiting the loop, it reads the alu entry and report to
> the user space irrespective of entry is valid. It works till the valid
> entry. If the loop exited when search is complete, it reads the alu
> table. The table returns all ones and it is reported to user space. So
> bridge fdb show gives ff:ff:ff:ff:ff:ff as last entry for every port.
> To fix it, after exiting the loop the entry is reported only if it is
> valid one.
> 
> Fixes: c2e866911e25 ("net: dsa: microchip: break KSZ9477 DSA driver into two files")

I think this should be:
Fixes: b987e98e50ab ("dsa: add DSA switch driver for Microchip KSZ9477")
since that's when ksz9477_port_fdb_dump() was introduced, with identical
logic.

> Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
> ---
>  drivers/net/dsa/microchip/ksz9477.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
> index 4b14d80d27ed..aa961dc03ddf 100644
> --- a/drivers/net/dsa/microchip/ksz9477.c
> +++ b/drivers/net/dsa/microchip/ksz9477.c
> @@ -613,15 +613,17 @@ int ksz9477_fdb_dump(struct ksz_device *dev, int port,
>  			goto exit;
>  		}
>  
> -		/* read ALU table */
> -		ksz9477_read_table(dev, alu_table);
> +		if (ksz_data & ALU_VALID) {

I wonder if you could avoid increasing the indentation level using:

		if (!(ksz_data & ALU_VALID))
			continue;

> +			/* read ALU table */
> +			ksz9477_read_table(dev, alu_table);
>  
> -		ksz9477_convert_alu(&alu, alu_table);
> +			ksz9477_convert_alu(&alu, alu_table);
>  
> -		if (alu.port_forward & BIT(port)) {
> -			ret = cb(alu.mac, alu.fid, alu.is_static, data);
> -			if (ret)
> -				goto exit;
> +			if (alu.port_forward & BIT(port)) {
> +				ret = cb(alu.mac, alu.fid, alu.is_static, data);
> +				if (ret)
> +					goto exit;
> +			}
>  		}
>  	} while (ksz_data & ALU_START);
>  
> 
> base-commit: f86d1fbbe7858884d6754534a0afbb74fc30bc26
> -- 
> 2.36.1
>