mlxsw: spectrum: Fix refcount bug on span entries

When binding port to a newly created span entry, its refcount is
initialized to zero even though it has a bound port. That leads
to unexpected behaviour when the user tries to delete that port
from the span entry.

Fix this by initializing the reference count to 1.

Also add a warning to put function.

Fixes: 763b4b70afcd ("mlxsw: spectrum: Add support in matchall mirror TC offloading")
Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 1ec0a4ce3c46edddc4fc0d63e67706d6459e10f3..dda5761e91bcbe27738cafd79d73e5a25f1f8b66 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -231,7 +231,7 @@ mlxsw_sp_span_entry_create(struct mlxsw_sp_port *port)
 
        span_entry->used = true;
        span_entry->id = index;
-       span_entry->ref_count = 0;
+       span_entry->ref_count = 1;
        span_entry->local_port = local_port;
        return span_entry;
 }
@@ -270,6 +270,7 @@ static struct mlxsw_sp_span_entry
 
        span_entry = mlxsw_sp_span_entry_find(port);
        if (span_entry) {
+               /* Already exists, just take a reference */
                span_entry->ref_count++;
                return span_entry;
        }
@@ -280,6 +281,7 @@ static struct mlxsw_sp_span_entry
 static int mlxsw_sp_span_entry_put(struct mlxsw_sp *mlxsw_sp,
                                   struct mlxsw_sp_span_entry *span_entry)
 {
+       WARN_ON(!span_entry->ref_count);
        if (--span_entry->ref_count == 0)
                mlxsw_sp_span_entry_destroy(mlxsw_sp, span_entry);
        return 0;