Merge branch 'xdp-bpf-fixes'

John Fastabend says:

====================
net: Fixes for XDP/BPF

The following fixes, UAPI updates, and small improvement,

i. XDP needs to be called inside RCU with preempt disabled.

ii. Not strictly a bug fix but we have an attach command in the
sockmap UAPI already to avoid having a single kernel released with
only the attach and not the detach I'm pushing this into net branch.
Its early in the RC cycle so I think this is OK (not ideal but better
than supporting a UAPI with a missing detach forever).

iii. Final patch replace cpu_relax with cond_resched in devmap.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 9 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 6f845e4fec17..fb766d906148 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3981,8 +3981,13 @@ static int netif_rx_internal(struct sk_buff *skb)
         trace_netif_rx(skb);
 
         if (static_key_false(&generic_xdp_needed)) {
-                int ret = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog),
-                                         skb);
+                int ret;
+
+                preempt_disable();
+                rcu_read_lock();
+                ret = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
+                rcu_read_unlock();
+                preempt_enable();
 
                 /* Consider XDP consuming the packet a success from
                  * the netdev point of view we do not want to count
@@ -4500,18 +4505,20 @@ static int netif_receive_skb_internal(struct sk_buff *skb)
         if (skb_defer_rx_timestamp(skb))
                 return NET_RX_SUCCESS;
 
-        rcu_read_lock();
-
         if (static_key_false(&generic_xdp_needed)) {
-                int ret = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog),
-                                         skb);
+                int ret;
 
-                if (ret != XDP_PASS) {
-                        rcu_read_unlock();
+                preempt_disable();
+                rcu_read_lock();
+                ret = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
+                rcu_read_unlock();
+                preempt_enable();
+
+                if (ret != XDP_PASS)
                         return NET_RX_DROP;
-                }
         }
 
+        rcu_read_lock();
 #ifdef CONFIG_RPS
         if (static_key_false(&rps_needed)) {
                 struct rps_dev_flow voidflow, *rflow = &voidflow;