net: socket: add __sys_socket() helper; remove in-kernel call to syscall

Using the net-internal helper __sys_socket() allows us to avoid the
internal calls to the sys_socket() syscall.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

diff --git a/include/linux/socket.h b/include/linux/socket.h
index 6a9840271676e63febd8184324ddadb0a6cb0b58..f8d040434a135e9efe6cd1a4761749b9ab3584c8 100644 (file)
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -363,5 +363,6 @@ extern int __sys_sendto(int fd, void __user *buff, size_t len,
                        int addr_len);
 extern int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
                         int __user *upeer_addrlen, int flags);
+extern int __sys_socket(int family, int type, int protocol);
 
 #endif /* _LINUX_SOCKET_H */

diff --git a/net/compat.c b/net/compat.c
index 0ff9f7451b6f54b04a474f6575e121eecdee730a..5b3b74c5812e9e2417350695c7faff572260f040 100644 (file)
--- a/net/compat.c
+++ b/net/compat.c
@@ -811,7 +811,7 @@ COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args)
 
        switch (call) {
        case SYS_SOCKET:
-               ret = sys_socket(a0, a1, a[2]);
+               ret = __sys_socket(a0, a1, a[2]);
                break;
        case SYS_BIND:
                ret = sys_bind(a0, compat_ptr(a1), a[2]);

diff --git a/net/socket.c b/net/socket.c
index 45f6ea0d57a5f15351276a2d69842c930ba09c75..07f379e50def3ee31ea0f0074ee41154ccb07b87 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -1332,7 +1332,7 @@ int sock_create_kern(struct net *net, int family, int type, int protocol, struct
 }
 EXPORT_SYMBOL(sock_create_kern);
 
-SYSCALL_DEFINE3(socket, int, family, int, type, int, protocol)
+int __sys_socket(int family, int type, int protocol)
 {
        int retval;
        struct socket *sock;
@@ -1359,6 +1359,11 @@ SYSCALL_DEFINE3(socket, int, family, int, type, int, protocol)
        return sock_map_fd(sock, flags & (O_CLOEXEC | O_NONBLOCK));
 }
 
+SYSCALL_DEFINE3(socket, int, family, int, type, int, protocol)
+{
+       return __sys_socket(family, type, protocol);
+}
+
 /*
  *     Create a pair of connected sockets.
  */
@@ -2463,7 +2468,7 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args)
 
        switch (call) {
        case SYS_SOCKET:
-               err = sys_socket(a0, a1, a[2]);
+               err = __sys_socket(a0, a1, a[2]);
                break;
        case SYS_BIND:
                err = sys_bind(a0, (struct sockaddr __user *)a1, a[2]);