net: dsa: microchip: ksz9477: fix fdb_dump last invalid entry

commit 36c0d935015766bf20d621c18313f17691bda5e3 upstream.

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: b987e98e50ab ("dsa: add DSA switch driver for Microchip KSZ9477")
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20220816105516.18350-1-arun.ramadoss@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index ab40b700cf1af8bc78a50fbf394d35fa41e31bf1..ebad795e4e95fc3eef1133f03128e6b56cadd285 100644 (file)
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -658,6 +658,9 @@ static int ksz9477_port_fdb_dump(struct dsa_switch *ds, int port,
                        goto exit;
                }
 
+               if (!(ksz_data & ALU_VALID))
+                       continue;
+
                /* read ALU table */
                ksz9477_read_table(dev, alu_table);