tcp: perform DMA to userspace only if there is a task waiting for it

[karo-tx-linux.git] / net / ipv4 / tcp_input.c

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 257b61789eeba9fd064470c91e3a8bffb8d1812d..56a9c8d0bef1300aa5dd204b0b23a21374dbd865 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5441,7 +5441,9 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                        if (tp->copied_seq == tp->rcv_nxt &&
                            len - tcp_header_len <= tp->ucopy.len) {
 #ifdef CONFIG_NET_DMA
-                               if (tcp_dma_try_early_copy(sk, skb, tcp_header_len)) {
+                               if (tp->ucopy.task == current &&
+                                   sock_owned_by_user(sk) &&
+                                   tcp_dma_try_early_copy(sk, skb, tcp_header_len)) {
                                        copied_early = 1;
                                        eaten = 1;
                                }