6 files changed, 41 insertions, 1 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 6f99c8f51b60..3213c7227b59 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1942,6 +1942,8 @@ enum netdev_ml_priv_type {
  *			dev->addr_list_lock.
  *	@unlink_list:	As netif_addr_lock() can be called recursively,
  *			keep a list of interfaces to be deleted.
+ *	@gro_max_size:	Maximum size of aggregated packet in generic
+ *			receive offload (GRO)
  *
  *	@dev_addr_shadow:	Copy of @dev_addr to catch direct writes.
  *	@linkwatch_dev_tracker:	refcount tracker used by linkwatch.
@@ -2131,6 +2133,8 @@ struct net_device {
 	struct bpf_prog __rcu	*xdp_prog;
 	unsigned long		gro_flush_timeout;
 	int			napi_defer_hard_irqs;
+#define GRO_MAX_SIZE		65536
+	unsigned int		gro_max_size;
 	rx_handler_func_t __rcu	*rx_handler;
 	void __rcu		*rx_handler_data;
 
@@ -4806,6 +4810,13 @@ static inline void netif_set_gso_max_segs(struct net_device *dev,
 	WRITE_ONCE(dev->gso_max_segs, segs);
 }
 
+static inline void netif_set_gro_max_size(struct net_device *dev,
+					  unsigned int size)
+{
+	/* This pairs with the READ_ONCE() in skb_gro_receive() */
+	WRITE_ONCE(dev->gro_max_size, size);
+}
+
 static inline void skb_gso_error_unwind(struct sk_buff *skb, __be16 protocol,
 					int pulled_hlen, u16 mac_offset,
 					int mac_len)
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 4ac53b30b6dc..6218f93f5c1a 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -347,6 +347,7 @@ enum {
 	 */
 	IFLA_PARENT_DEV_NAME,
 	IFLA_PARENT_DEV_BUS_NAME,
+	IFLA_GRO_MAX_SIZE,
 
 	__IFLA_MAX
 };
diff --git a/net/core/dev.c b/net/core/dev.c
index 6c8b226b5f2f..83a4089990a0 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10180,6 +10180,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 
 	dev->gso_max_size = GSO_MAX_SIZE;
 	dev->gso_max_segs = GSO_MAX_SEGS;
+	dev->gro_max_size = GRO_MAX_SIZE;
 	dev->upper_level = 1;
 	dev->lower_level = 1;
 #ifdef CONFIG_LOCKDEP
diff --git a/net/core/gro.c b/net/core/gro.c
index 8ec8b44596da..a11b286d1495 100644
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -132,10 +132,14 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
 	unsigned int headlen = skb_headlen(skb);
 	unsigned int len = skb_gro_len(skb);
 	unsigned int delta_truesize;
+	unsigned int gro_max_size;
 	unsigned int new_truesize;
 	struct sk_buff *lp;
 
-	if (unlikely(p->len + len >= 65536 || NAPI_GRO_CB(skb)->flush))
+	/* pairs with WRITE_ONCE() in netif_set_gro_max_size() */
+	gro_max_size = READ_ONCE(p->dev->gro_max_size);
+
+	if (unlikely(p->len + len >= gro_max_size || NAPI_GRO_CB(skb)->flush))
 		return -E2BIG;
 
 	lp = NAPI_GRO_CB(p)->last;
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d6eba554b137..e476403231f0 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1026,6 +1026,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + nla_total_size(4) /* IFLA_NUM_RX_QUEUES */
 	       + nla_total_size(4) /* IFLA_GSO_MAX_SEGS */
 	       + nla_total_size(4) /* IFLA_GSO_MAX_SIZE */
+	       + nla_total_size(4) /* IFLA_GRO_MAX_SIZE */
 	       + nla_total_size(1) /* IFLA_OPERSTATE */
 	       + nla_total_size(1) /* IFLA_LINKMODE */
 	       + nla_total_size(4) /* IFLA_CARRIER_CHANGES */
@@ -1728,6 +1729,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
 	    nla_put_u32(skb, IFLA_NUM_TX_QUEUES, dev->num_tx_queues) ||
 	    nla_put_u32(skb, IFLA_GSO_MAX_SEGS, dev->gso_max_segs) ||
 	    nla_put_u32(skb, IFLA_GSO_MAX_SIZE, dev->gso_max_size) ||
+	    nla_put_u32(skb, IFLA_GRO_MAX_SIZE, dev->gro_max_size) ||
 #ifdef CONFIG_RPS
 	    nla_put_u32(skb, IFLA_NUM_RX_QUEUES, dev->num_rx_queues) ||
 #endif
@@ -1880,6 +1882,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
 	[IFLA_PROTO_DOWN_REASON] = { .type = NLA_NESTED },
 	[IFLA_NEW_IFINDEX]	= NLA_POLICY_MIN(NLA_S32, 1),
 	[IFLA_PARENT_DEV_NAME]	= { .type = NLA_NUL_STRING },
+	[IFLA_GRO_MAX_SIZE]	= { .type = NLA_U32 },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -2299,6 +2302,14 @@ static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[],
 		}
 	}
 
+	if (tb[IFLA_GRO_MAX_SIZE]) {
+		u32 gro_max_size = nla_get_u32(tb[IFLA_GRO_MAX_SIZE]);
+
+		if (gro_max_size > GRO_MAX_SIZE) {
+			NL_SET_ERR_MSG(extack, "too big gro_max_size");
+			return -EINVAL;
+		}
+	}
 	return 0;
 }
 
@@ -2772,6 +2783,15 @@ static int do_setlink(const struct sk_buff *skb,
 		}
 	}
 
+	if (tb[IFLA_GRO_MAX_SIZE]) {
+		u32 gro_max_size = nla_get_u32(tb[IFLA_GRO_MAX_SIZE]);
+
+		if (dev->gro_max_size ^ gro_max_size) {
+			netif_set_gro_max_size(dev, gro_max_size);
+			status |= DO_SETLINK_MODIFIED;
+		}
+	}
+
 	if (tb[IFLA_OPERSTATE])
 		set_operstate(dev, nla_get_u8(tb[IFLA_OPERSTATE]));
 
@@ -3222,6 +3242,8 @@ struct net_device *rtnl_create_link(struct net *net, const char *ifname,
 		netif_set_gso_max_size(dev, nla_get_u32(tb[IFLA_GSO_MAX_SIZE]));
 	if (tb[IFLA_GSO_MAX_SEGS])
 		netif_set_gso_max_segs(dev, nla_get_u32(tb[IFLA_GSO_MAX_SEGS]));
+	if (tb[IFLA_GRO_MAX_SIZE])
+		netif_set_gro_max_size(dev, nla_get_u32(tb[IFLA_GRO_MAX_SIZE]));
 
 	return dev;
 }
diff --git a/tools/include/uapi/linux/if_link.h b/tools/include/uapi/linux/if_link.h
index 4ac53b30b6dc..6218f93f5c1a 100644
--- a/tools/include/uapi/linux/if_link.h
+++ b/tools/include/uapi/linux/if_link.h
@@ -347,6 +347,7 @@ enum {
 	 */
 	IFLA_PARENT_DEV_NAME,
 	IFLA_PARENT_DEV_BUS_NAME,
+	IFLA_GRO_MAX_SIZE,
 
 	__IFLA_MAX
 };