[PATCHv3 net 2/3] net: cls_u32: be more strict about skip-sw flag

[Jakub Kicinski]

Return an error if user requested skip-sw and the underlaying
hardware cannot handle tc offloads (or offloads are disabled).

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
Reviewed-by: Dinan Gunawardena <dgunaward...@netronome.com>
Reviewed-by: Simon Horman <simon.hor...@netronome.com>
---
v2:
  - handle both knode and hnodes
---
 net/sched/cls_u32.c | 58 +++++++++++++++++++++++++++--------------------------
 1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index b17e090f2fe1..0fc1d47885f8 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -457,20 +457,21 @@ static int u32_replace_hw_hnode(struct tcf_proto *tp,
        struct tc_to_netdev offload;
        int err;
 
+       if (!tc_should_offload(dev, flags))
+               return tc_skip_sw(flags) ? -EINVAL : 0;
+
        offload.type = TC_SETUP_CLSU32;
        offload.cls_u32 = &u32_offload;
 
-       if (tc_should_offload(dev, flags)) {
-               offload.cls_u32->command = TC_CLSU32_NEW_HNODE;
-               offload.cls_u32->hnode.divisor = h->divisor;
-               offload.cls_u32->hnode.handle = h->handle;
-               offload.cls_u32->hnode.prio = h->prio;
+       offload.cls_u32->command = TC_CLSU32_NEW_HNODE;
+       offload.cls_u32->hnode.divisor = h->divisor;
+       offload.cls_u32->hnode.handle = h->handle;
+       offload.cls_u32->hnode.prio = h->prio;
 
-               err = dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle,
-                                                   tp->protocol, &offload);
-               if (tc_skip_sw(flags))
-                       return err;
-       }
+       err = dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle,
+                                           tp->protocol, &offload);
+       if (tc_skip_sw(flags))
+               return err;
 
        return 0;
 }
@@ -507,27 +508,28 @@ static int u32_replace_hw_knode(struct tcf_proto *tp,
        offload.type = TC_SETUP_CLSU32;
        offload.cls_u32 = &u32_offload;
 
-       if (tc_should_offload(dev, flags)) {
-               offload.cls_u32->command = TC_CLSU32_REPLACE_KNODE;
-               offload.cls_u32->knode.handle = n->handle;
-               offload.cls_u32->knode.fshift = n->fshift;
+       if (!tc_should_offload(dev, flags))
+               return tc_skip_sw(flags) ? -EINVAL : 0;
+
+       offload.cls_u32->command = TC_CLSU32_REPLACE_KNODE;
+       offload.cls_u32->knode.handle = n->handle;
+       offload.cls_u32->knode.fshift = n->fshift;
 #ifdef CONFIG_CLS_U32_MARK
-               offload.cls_u32->knode.val = n->val;
-               offload.cls_u32->knode.mask = n->mask;
+       offload.cls_u32->knode.val = n->val;
+       offload.cls_u32->knode.mask = n->mask;
 #else
-               offload.cls_u32->knode.val = 0;
-               offload.cls_u32->knode.mask = 0;
+       offload.cls_u32->knode.val = 0;
+       offload.cls_u32->knode.mask = 0;
 #endif
-               offload.cls_u32->knode.sel = &n->sel;
-               offload.cls_u32->knode.exts = &n->exts;
-               if (n->ht_down)
-                       offload.cls_u32->knode.link_handle = n->ht_down->handle;
-
-               err = dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle,
-                                                   tp->protocol, &offload);
-               if (tc_skip_sw(flags))
-                       return err;
-       }
+       offload.cls_u32->knode.sel = &n->sel;
+       offload.cls_u32->knode.exts = &n->exts;
+       if (n->ht_down)
+               offload.cls_u32->knode.link_handle = n->ht_down->handle;
+
+       err = dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle,
+                                           tp->protocol, &offload);
+       if (tc_skip_sw(flags))
+               return err;
 
        return 0;
 }
-- 
1.9.1