mlxsw: spectrum: Fix refcount bug on span entries

[ Upstream commit 2d644d4c7506646f9c4a2afceb7fd5f030bc0c9f ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index d48873bcbddfc0d0049ecc2f73b5bfcc68862d20..5cdc96bdd4449849f6b634f7d0f49a3409fbd23a 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;
 }
@@ -268,6 +268,7 @@ struct mlxsw_sp_span_entry *mlxsw_sp_span_entry_get(struct mlxsw_sp_port *port)
 
        span_entry = mlxsw_sp_span_entry_find(port);
        if (span_entry) {
+               /* Already exists, just take a reference */
                span_entry->ref_count++;
                return span_entry;
        }
@@ -278,6 +279,7 @@ struct mlxsw_sp_span_entry *mlxsw_sp_span_entry_get(struct mlxsw_sp_port *port)
 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;