svcrpc: don't hold sv_lock over svc_xprt_put()

svc_xprt_put() can call tcp_close(), which can sleep, so we shouldn't be
holding this lock.

In fact, only the xpt_list removal and the sv_tmpcnt decrement should
need the sv_lock here.
Reported-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

net/sunrpc/svc_xprt.c

@@ -892,12 +892,12 @@ void svc_delete_xprt(struct svc_xprt *xprt)
 	 */
 	if (test_bit(XPT_TEMP, &xprt->xpt_flags))
 		serv->sv_tmpcnt--;
+	spin_unlock_bh(&serv->sv_lock);
 
 	while ((dr = svc_deferred_dequeue(xprt)) != NULL)
 		kfree(dr);
 
 	svc_xprt_put(xprt);
-	spin_unlock_bh(&serv->sv_lock);
 }
 
 void svc_close_xprt(struct svc_xprt *xprt)