netdev - [PATCH bpf-next] xsk, net: make sock_def_readable() have external linkage

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Date:   Mon, 20 Jan 2020 10:29:17 +0100
From:   Björn Töpel <bjorn.topel@...il.com>
To:     netdev@...r.kernel.org, ast@...nel.org, daniel@...earbox.net
Cc:     Björn Töpel <bjorn.topel@...el.com>,
        bpf@...r.kernel.org, magnus.karlsson@...el.com,
        jonathan.lemon@...il.com
Subject: [PATCH bpf-next] xsk, net: make sock_def_readable() have external linkage

From: Björn Töpel <bjorn.topel@...el.com>

XDP sockets use the default implementation of struct sock's
sk_data_ready callback, which is sock_def_readable(). This function is
called in the XDP socket fast-path, and involves a retpoline. By
letting sock_def_readable() have external linkage, and being called
directly, the retpoline can be avoided.

Signed-off-by: Björn Töpel <bjorn.topel@...el.com>
---
 include/net/sock.h | 2 ++
 net/core/sock.c    | 2 +-
 net/xdp/xsk.c      | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 8dff68b4c316..0891c55f1e82 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2612,4 +2612,6 @@ static inline bool sk_dev_equal_l3scope(struct sock *sk, int dif)
 	return false;
 }
 
+void sock_def_readable(struct sock *sk);
+
 #endif	/* _SOCK_H */
diff --git a/net/core/sock.c b/net/core/sock.c
index 8459ad579f73..a4c8fac781ff 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2786,7 +2786,7 @@ static void sock_def_error_report(struct sock *sk)
 	rcu_read_unlock();
 }
 
-static void sock_def_readable(struct sock *sk)
+void sock_def_readable(struct sock *sk)
 {
 	struct socket_wq *wq;
 
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 02ada7ab8c6e..df600487a68d 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -217,7 +217,7 @@ static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 static void xsk_flush(struct xdp_sock *xs)
 {
 	xskq_prod_submit(xs->rx);
-	xs->sk.sk_data_ready(&xs->sk);
+	sock_def_readable(&xs->sk);
 }
 
 int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
-- 
2.20.1