1 files changed, 72 insertions, 4 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index 9abc4fe25953..fe87f9bd8f16 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -124,6 +124,7 @@
 #include <linux/netdevice.h>
 #include <net/protocol.h>
 #include <linux/skbuff.h>
+#include <linux/skbuff_ref.h>
 #include <net/net_namespace.h>
 #include <net/request_sock.h>
 #include <net/sock.h>
@@ -1049,6 +1050,69 @@ static int sock_reserve_memory(struct sock *sk, int bytes)
 	return 0;
 }
 
+#ifdef CONFIG_PAGE_POOL
+
+/* This is the number of tokens that the user can SO_DEVMEM_DONTNEED in
+ * 1 syscall. The limit exists to limit the amount of memory the kernel
+ * allocates to copy these tokens.
+ */
+#define MAX_DONTNEED_TOKENS 128
+
+static noinline_for_stack int
+sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optlen)
+{
+	unsigned int num_tokens, i, j, k, netmem_num = 0;
+	struct dmabuf_token *tokens;
+	netmem_ref netmems[16];
+	int ret = 0;
+
+	if (!sk_is_tcp(sk))
+		return -EBADF;
+
+	if (optlen % sizeof(struct dmabuf_token) ||
+	    optlen > sizeof(*tokens) * MAX_DONTNEED_TOKENS)
+		return -EINVAL;
+
+	tokens = kvmalloc_array(optlen, sizeof(*tokens), GFP_KERNEL);
+	if (!tokens)
+		return -ENOMEM;
+
+	num_tokens = optlen / sizeof(struct dmabuf_token);
+	if (copy_from_sockptr(tokens, optval, optlen)) {
+		kvfree(tokens);
+		return -EFAULT;
+	}
+
+	xa_lock_bh(&sk->sk_user_frags);
+	for (i = 0; i < num_tokens; i++) {
+		for (j = 0; j < tokens[i].token_count; j++) {
+			netmem_ref netmem = (__force netmem_ref)__xa_erase(
+				&sk->sk_user_frags, tokens[i].token_start + j);
+
+			if (netmem &&
+			    !WARN_ON_ONCE(!netmem_is_net_iov(netmem))) {
+				netmems[netmem_num++] = netmem;
+				if (netmem_num == ARRAY_SIZE(netmems)) {
+					xa_unlock_bh(&sk->sk_user_frags);
+					for (k = 0; k < netmem_num; k++)
+						WARN_ON_ONCE(!napi_pp_put_page(netmems[k]));
+					netmem_num = 0;
+					xa_lock_bh(&sk->sk_user_frags);
+				}
+				ret++;
+			}
+		}
+	}
+
+	xa_unlock_bh(&sk->sk_user_frags);
+	for (k = 0; k < netmem_num; k++)
+		WARN_ON_ONCE(!napi_pp_put_page(netmems[k]));
+
+	kvfree(tokens);
+	return ret;
+}
+#endif
+
 void sockopt_lock_sock(struct sock *sk)
 {
 	/* When current->bpf_ctx is set, the setsockopt is called from
@@ -1211,6 +1275,10 @@ int sk_setsockopt(struct sock *sk, int level, int optname,
 			ret = -EOPNOTSUPP;
 		return ret;
 		}
+#ifdef CONFIG_PAGE_POOL
+	case SO_DEVMEM_DONTNEED:
+		return sock_devmem_dontneed(sk, optval, optlen);
+#endif
 	}
 
 	sockopt_lock_sock(sk);
@@ -2048,7 +2116,7 @@ static inline void sock_lock_init(struct sock *sk)
 
 /*
  * Copy all fields from osk to nsk but nsk->sk_refcnt must not change yet,
- * even temporarly, because of RCU lookups. sk_node should also be left as is.
+ * even temporarily, because of RCU lookups. sk_node should also be left as is.
  * We must not copy fields between sk_dontcopy_begin and sk_dontcopy_end
  */
 static void sock_copy(struct sock *nsk, const struct sock *osk)
@@ -2538,7 +2606,7 @@ void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
 	skb_set_hash_from_sk(skb, sk);
 	/*
 	 * We used to take a refcount on sk, but following operation
-	 * is enough to guarantee sk_free() wont free this sock until
+	 * is enough to guarantee sk_free() won't free this sock until
 	 * all in-flight packets are completed
 	 */
 	refcount_add(skb->truesize, &sk->sk_wmem_alloc);
@@ -3429,7 +3497,7 @@ static void sock_def_destruct(struct sock *sk)
 void sk_send_sigurg(struct sock *sk)
 {
 	if (sk->sk_socket && sk->sk_socket->file)
-		if (send_sigurg(&sk->sk_socket->file->f_owner))
+		if (send_sigurg(sk->sk_socket->file))
 			sk_wake_async(sk, SOCK_WAKE_URG, POLL_PRI);
 }
 EXPORT_SYMBOL(sk_send_sigurg);
@@ -3697,7 +3765,7 @@ EXPORT_SYMBOL(sock_recv_errqueue);
  *
  *	FIX: POSIX 1003.1g is very ambiguous here. It states that
  *	asynchronous errors should be reported by getsockopt. We assume
- *	this means if you specify SO_ERROR (otherwise whats the point of it).
+ *	this means if you specify SO_ERROR (otherwise what is the point of it).
  */
 int sock_common_getsockopt(struct socket *sock, int level, int optname,
 			   char __user *optval, int __user *optlen)