Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

[platform/kernel/linux-rpi.git] / net / core / dev.c

diff --git a/net/core/dev.c b/net/core/dev.c
index eaaeff4..8865079 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7532,7 +7532,7 @@ void *netdev_lower_get_next_private_rcu(struct net_device *dev,
 {
        struct netdev_adjacent *lower;
 
-       WARN_ON_ONCE(!rcu_read_lock_held());
+       WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
 
        lower = list_entry_rcu((*iter)->next, struct netdev_adjacent, list);
 
@@ -9297,7 +9297,7 @@ static struct bpf_prog *dev_xdp_prog(struct net_device *dev,
        return dev->xdp_state[mode].prog;
 }
 
-static u8 dev_xdp_prog_count(struct net_device *dev)
+u8 dev_xdp_prog_count(struct net_device *dev)
 {
        u8 count = 0;
        int i;
@@ -9307,6 +9307,7 @@ static u8 dev_xdp_prog_count(struct net_device *dev)
                        count++;
        return count;
 }
+EXPORT_SYMBOL_GPL(dev_xdp_prog_count);
 
 u32 dev_xdp_prog_id(struct net_device *dev, enum bpf_xdp_mode mode)
 {
@@ -9400,6 +9401,8 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack
 {
        unsigned int num_modes = hweight32(flags & XDP_FLAGS_MODES);
        struct bpf_prog *cur_prog;
+       struct net_device *upper;
+       struct list_head *iter;
        enum bpf_xdp_mode mode;
        bpf_op_t bpf_op;
        int err;
@@ -9438,6 +9441,14 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack
                return -EBUSY;
        }
 
+       /* don't allow if an upper device already has a program */
+       netdev_for_each_upper_dev_rcu(dev, upper, iter) {
+               if (dev_xdp_prog_count(upper) > 0) {
+                       NL_SET_ERR_MSG(extack, "Cannot attach when an upper device already has a program");
+                       return -EEXIST;
+               }
+       }
+
        cur_prog = dev_xdp_prog(dev, mode);
        /* can't replace attached prog with link */
        if (link && cur_prog) {