net: busy-poll: remove need_resched() from sk_can_busy_loop()

Now sk_busy_loop() can schedule by itself, we can remove
need_resched() check from sk_can_busy_loop()

Also add a const to its struct sock parameter.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Adam Belay <abelay@google.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Yuval Mintz <Yuval.Mintz@cavium.com>
Cc: Ariel Elior <ariel.elior@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: edumazet

include/net/busy_poll.h

@@ -58,10 +58,9 @@ static inline unsigned long busy_loop_end_time(void)
 	return busy_loop_us_clock() + ACCESS_ONCE(sysctl_net_busy_poll);
 }
 
-static inline bool sk_can_busy_loop(struct sock *sk)
+static inline bool sk_can_busy_loop(const struct sock *sk)
 {
-	return sk->sk_ll_usec && sk->sk_napi_id &&
-	       !need_resched() && !signal_pending(current);
+	return sk->sk_ll_usec && sk->sk_napi_id && !signal_pending(current);
 }