[PATCH bpf-next 2/3] nfp: allow apps to request larger MTU on control vNIC

[Jakub Kicinski]

Some apps may want to have higher MTU on the control vNIC/queue.
Allow them to set the requested MTU at init time.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
 drivers/net/ethernet/netronome/nfp/nfp_app.h       |  4 ++++
 .../net/ethernet/netronome/nfp/nfp_net_common.c    | 14 ++++++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_app.h 
b/drivers/net/ethernet/netronome/nfp/nfp_app.h
index 4e1eb3395648..c896eb8f87a1 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_app.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_app.h
@@ -40,6 +40,8 @@
 
 #include "nfp_net_repr.h"
 
+#define NFP_APP_CTRL_MTU_MAX   U32_MAX
+
 struct bpf_prog;
 struct net_device;
 struct netdev_bpf;
@@ -178,6 +180,7 @@ struct nfp_app_type {
  * @ctrl:      pointer to ctrl vNIC struct
  * @reprs:     array of pointers to representors
  * @type:      pointer to const application ops and info
+ * @ctrl_mtu:  MTU to set on the control vNIC (set in .init())
  * @priv:      app-specific priv data
  */
 struct nfp_app {
@@ -189,6 +192,7 @@ struct nfp_app {
        struct nfp_reprs __rcu *reprs[NFP_REPR_TYPE_MAX + 1];
 
        const struct nfp_app_type *type;
+       unsigned int ctrl_mtu;
        void *priv;
 };
 
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c 
b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index d05e37fcc1b2..8e8dc0db2493 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -3877,10 +3877,20 @@ int nfp_net_init(struct nfp_net *nn)
                return err;
 
        /* Set default MTU and Freelist buffer size */
-       if (nn->max_mtu < NFP_NET_DEFAULT_MTU)
+       if (!nfp_net_is_data_vnic(nn) && nn->app->ctrl_mtu) {
+               if (nn->app->ctrl_mtu <= nn->max_mtu) {
+                       nn->dp.mtu = nn->app->ctrl_mtu;
+               } else {
+                       if (nn->app->ctrl_mtu != NFP_APP_CTRL_MTU_MAX)
+                               nn_warn(nn, "app requested MTU above max 
supported %u > %u\n",
+                                       nn->app->ctrl_mtu, nn->max_mtu);
+                       nn->dp.mtu = nn->max_mtu;
+               }
+       } else if (nn->max_mtu < NFP_NET_DEFAULT_MTU) {
                nn->dp.mtu = nn->max_mtu;
-       else
+       } else {
                nn->dp.mtu = NFP_NET_DEFAULT_MTU;
+       }
        nn->dp.fl_bufsz = nfp_net_calc_fl_bufsz(&nn->dp);
 
        if (nfp_app_ctrl_uses_data_vnics(nn->app))
-- 
2.17.1