net: cls_u32: be more strict about skip-sw flag for knodes

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

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 18 deletions

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 54ab32a8ff4c..ffe593efe930 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -508,27 +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, tp, 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, tp, 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;
 }