tcp: simplify tcp_current_mss
There's very little need for most of the callsites to get
tp->xmit_goal_size updated. That will cost us divide as is,
so slice the function in two. Also, the only users of the
tp->xmit_goal_size are directly behind tcp_current_mss(),
so there's no need to store that variable into tcp_sock
at all! The drop of xmit_goal_size currently leaves 16-bit
hole and some reorganization would again be necessary to
change that (but I'm aiming to fill that hole with u16
xmit_goal_size_segs to cache the results of the remaining
divide to get that tso on regression).
Bring xmit_goal_size parts into tcp.c
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index d3f9bee..886596f 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -661,6 +661,37 @@
return NULL;
}
+static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
+ int large_allowed)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ u32 xmit_size_goal;
+
+ xmit_size_goal = mss_now;
+
+ if (large_allowed && sk_can_gso(sk)) {
+ xmit_size_goal = ((sk->sk_gso_max_size - 1) -
+ inet_csk(sk)->icsk_af_ops->net_header_len -
+ inet_csk(sk)->icsk_ext_hdr_len -
+ tp->tcp_header_len);
+
+ xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
+ xmit_size_goal -= (xmit_size_goal % mss_now);
+ }
+
+ return xmit_size_goal;
+}
+
+static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
+{
+ int mss_now;
+
+ mss_now = tcp_current_mss(sk);
+ *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
+
+ return mss_now;
+}
+
static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
size_t psize, int flags)
{
@@ -677,8 +708,7 @@
clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
- mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
- size_goal = tp->xmit_size_goal;
+ mss_now = tcp_send_mss(sk, &size_goal, flags);
copied = 0;
err = -EPIPE;
@@ -761,8 +791,7 @@
if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
goto do_error;
- mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
- size_goal = tp->xmit_size_goal;
+ mss_now = tcp_send_mss(sk, &size_goal, flags);
}
out:
@@ -844,8 +873,7 @@
/* This should be in poll */
clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
- mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
- size_goal = tp->xmit_size_goal;
+ mss_now = tcp_send_mss(sk, &size_goal, flags);
/* Ok commence sending. */
iovlen = msg->msg_iovlen;
@@ -1007,8 +1035,7 @@
if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
goto do_error;
- mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
- size_goal = tp->xmit_size_goal;
+ mss_now = tcp_send_mss(sk, &size_goal, flags);
}
}