net/mlx5: Fix bridge mode operations when there are no VFs

Currently, trying to set the bridge mode attribute when numvfs=0 leads to a
crash:

bridge link set dev eth2 hwmode vepa

[  168.967392] BUG: kernel NULL pointer dereference, address: 0000000000000030
[...]
[  168.969989] RIP: 0010:mlx5_add_flow_rules+0x1f/0x300 [mlx5_core]
[...]
[  168.976037] Call Trace:
[  168.976188]  <TASK>
[  168.978620]  _mlx5_eswitch_set_vepa_locked+0x113/0x230 [mlx5_core]
[  168.979074]  mlx5_eswitch_set_vepa+0x7f/0xa0 [mlx5_core]
[  168.979471]  rtnl_bridge_setlink+0xe9/0x1f0
[  168.979714]  rtnetlink_rcv_msg+0x159/0x400
[  168.980451]  netlink_rcv_skb+0x54/0x100
[  168.980675]  netlink_unicast+0x241/0x360
[  168.980918]  netlink_sendmsg+0x1f6/0x430
[  168.981162]  ____sys_sendmsg+0x3bb/0x3f0
[  168.982155]  ___sys_sendmsg+0x88/0xd0
[  168.985036]  __sys_sendmsg+0x59/0xa0
[  168.985477]  do_syscall_64+0x79/0x150
[  168.987273]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  168.987773] RIP: 0033:0x7f8f7950f917

(esw->fdb_table.legacy.vepa_fdb is null)

The bridge mode is only relevant when there are multiple functions per
port. Therefore, prevent setting and getting this setting when there are no
VFs.

Note that after this change, there are no settings to change on the PF
interface using `bridge link` when there are no VFs, so the interface no
longer appears in the `bridge link` output.

Fixes: 4b89251de024 ("net/mlx5: Support ndo bridge_setlink and getlink")
Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/esw/legacy.c b/drivers/net/ethernet/mellanox/mlx5/core/esw/legacy.c
index 255bc8b749f9a52139d0eb998154c1c4a5aae41e..8587cd572da536b45cf7088e658db940470c253d 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/esw/legacy.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/esw/legacy.c
@@ -319,7 +319,7 @@ int mlx5_eswitch_set_vepa(struct mlx5_eswitch *esw, u8 setting)
                return -EPERM;
 
        mutex_lock(&esw->state_lock);
-       if (esw->mode != MLX5_ESWITCH_LEGACY) {
+       if (esw->mode != MLX5_ESWITCH_LEGACY || !mlx5_esw_is_fdb_created(esw)) {
                err = -EOPNOTSUPP;
                goto out;
        }
@@ -339,7 +339,7 @@ int mlx5_eswitch_get_vepa(struct mlx5_eswitch *esw, u8 *setting)
        if (!mlx5_esw_allowed(esw))
                return -EPERM;
 
-       if (esw->mode != MLX5_ESWITCH_LEGACY)
+       if (esw->mode != MLX5_ESWITCH_LEGACY || !mlx5_esw_is_fdb_created(esw))
                return -EOPNOTSUPP;
 
        *setting = esw->fdb_table.legacy.vepa_uplink_rule ? 1 : 0;