[PATCH net-next 4/4] net: use indirect calls helpers at the socket layer

[Paolo Abeni]

This avoids an indirect call per {send,recv}msg syscall in
the common (IPv6 or IPv4 socket) case.

Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
 net/socket.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index a180e1a9ff23..472fbefa5d9b 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -90,6 +90,7 @@
 #include <linux/slab.h>
 #include <linux/xattr.h>
 #include <linux/nospec.h>
+#include <linux/indirect_call_wrapper.h>
 
 #include <linux/uaccess.h>
 #include <asm/unistd.h>
@@ -108,6 +109,13 @@
 #include <net/busy_poll.h>
 #include <linux/errqueue.h>
 
+/* proto_ops for ipv4 and ipv6 use the same {recv,send}msg function */
+#if IS_ENABLED(CONFIG_INET)
+#define INDIRECT_CALL_INET4(f, f1, ...) INDIRECT_CALL_1(f, f1, __VA_ARGS__)
+#else
+#define INDIRECT_CALL_INET4(f, f1, ...) f(__VA_ARGS__)
+#endif
+
 #ifdef CONFIG_NET_RX_BUSY_POLL
 unsigned int sysctl_net_busy_read __read_mostly;
 unsigned int sysctl_net_busy_poll __read_mostly;
@@ -645,10 +653,12 @@ EXPORT_SYMBOL(__sock_tx_timestamp);
  *     Sends @msg through @sock, passing through LSM.
  *     Returns the number of bytes sent, or an error code.
  */
-
+INDIRECT_CALLABLE_DECLARE(int inet_sendmsg(struct socket *, struct msghdr *,
+                                          size_t));
 static inline int sock_sendmsg_nosec(struct socket *sock, struct msghdr *msg)
 {
-       int ret = sock->ops->sendmsg(sock, msg, msg_data_left(msg));
+       int ret = INDIRECT_CALL_INET4(sock->ops->sendmsg, inet_sendmsg, sock,
+                                     msg, msg_data_left(msg));
        BUG_ON(ret == -EIOCBQUEUED);
        return ret;
 }
@@ -874,11 +884,13 @@ EXPORT_SYMBOL_GPL(__sock_recv_ts_and_drops);
  *     Receives @msg from @sock, passing through LSM. Returns the total number
  *     of bytes received, or an error.
  */
-
+INDIRECT_CALLABLE_DECLARE(int inet_recvmsg(struct socket *, struct msghdr *,
+                                          size_t , int ));
 static inline int sock_recvmsg_nosec(struct socket *sock, struct msghdr *msg,
                                     int flags)
 {
-       return sock->ops->recvmsg(sock, msg, msg_data_left(msg), flags);
+       return INDIRECT_CALL_INET4(sock->ops->recvmsg, inet_recvmsg, sock, msg,
+                                  msg_data_left(msg), flags);
 }
 
 int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags)
-- 
2.20.1