1 files changed, 57 insertions, 3 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 01810a3f19d..8e4062f165b 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -40,6 +40,7 @@
 #ifndef _SOCK_H
 #define _SOCK_H
 
+#include <linux/hardirq.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/list_nulls.h>
@@ -52,6 +53,7 @@
 #include <linux/mm.h>
 #include <linux/security.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 
 #include <linux/filter.h>
 #include <linux/rculist_nulls.h>
@@ -177,7 +179,6 @@ struct sock_common {
   *	@sk_dst_cache: destination cache
   *	@sk_dst_lock: destination cache lock
   *	@sk_policy: flow policy
-  *	@sk_rmem_alloc: receive queue bytes committed
   *	@sk_receive_queue: incoming packets
   *	@sk_wmem_alloc: transmit queue bytes committed
   *	@sk_write_queue: Packet sending queue
@@ -562,6 +563,7 @@ enum sock_flags {
 	SOCK_TIMESTAMPING_SYS_HARDWARE, /* %SOF_TIMESTAMPING_SYS_HARDWARE */
 	SOCK_FASYNC, /* fasync() active */
 	SOCK_RXQ_OVFL,
+	SOCK_ZEROCOPY, /* buffers from userspace */
 };
 
 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
@@ -1301,8 +1303,7 @@ extern unsigned long sock_i_ino(struct sock *sk);
 static inline struct dst_entry *
 __sk_dst_get(struct sock *sk)
 {
-	return rcu_dereference_check(sk->sk_dst_cache, rcu_read_lock_held() ||
-						       sock_owned_by_user(sk) ||
+	return rcu_dereference_check(sk->sk_dst_cache, sock_owned_by_user(sk) ||
 						       lockdep_is_held(&sk->sk_lock.slock));
 }
 
@@ -1389,6 +1390,59 @@ static inline void sk_nocaps_add(struct sock *sk, int flags)
 	sk->sk_route_caps &= ~flags;
 }
 
+static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
+					   char __user *from, char *to,
+					   int copy, int offset)
+{
+	if (skb->ip_summed == CHECKSUM_NONE) {
+		int err = 0;
+		__wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err);
+		if (err)
+			return err;
+		skb->csum = csum_block_add(skb->csum, csum, offset);
+	} else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
+		if (!access_ok(VERIFY_READ, from, copy) ||
+		    __copy_from_user_nocache(to, from, copy))
+			return -EFAULT;
+	} else if (copy_from_user(to, from, copy))
+		return -EFAULT;
+
+	return 0;
+}
+
+static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
+				       char __user *from, int copy)
+{
+	int err, offset = skb->len;
+
+	err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
+				       copy, offset);
+	if (err)
+		__skb_trim(skb, offset);
+
+	return err;
+}
+
+static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from,
+					   struct sk_buff *skb,
+					   struct page *page,
+					   int off, int copy)
+{
+	int err;
+
+	err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
+				       copy, skb->len);
+	if (err)
+		return err;
+
+	skb->len	     += copy;
+	skb->data_len	     += copy;
+	skb->truesize	     += copy;
+	sk->sk_wmem_queued   += copy;
+	sk_mem_charge(sk, copy);
+	return 0;
+}
+
 static inline int skb_copy_to_page(struct sock *sk, char __user *from,
 				   struct sk_buff *skb, struct page *page,
 				   int off, int copy)