1 files changed, 14 insertions, 6 deletions

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 932d6241b787..ce57f6a32bdf 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -424,10 +424,17 @@ static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
         if (!tty)
                 goto done;
 
-        /* Push data to tty */
-        for (i = 0; i < urb->actual_length; i++, ch++) {
-                if (!usb_serial_handle_sysrq_char(port, *ch))
-                        tty_insert_flip_char(tty, *ch, TTY_NORMAL);
+        /* The per character mucking around with sysrq path it too slow for
+           stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
+           where the USB serial is not a console anyway */
+        if (!port->console || !port->sysrq)
+                tty_insert_flip_string(tty, ch, urb->actual_length);
+        else {
+                /* Push data to tty */
+                for (i = 0; i < urb->actual_length; i++, ch++) {
+                        if (!usb_serial_handle_sysrq_char(tty, port, *ch))
+                                tty_insert_flip_char(tty, *ch, TTY_NORMAL);
+                }
         }
         tty_flip_buffer_push(tty);
         tty_kref_put(tty);
@@ -527,11 +534,12 @@ void usb_serial_generic_unthrottle(struct tty_struct *tty)
         }
 }
 
-int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
+int usb_serial_handle_sysrq_char(struct tty_struct *tty,
+                        struct usb_serial_port *port, unsigned int ch)
 {
         if (port->sysrq && port->console) {
                 if (ch && time_before(jiffies, port->sysrq)) {
-                        handle_sysrq(ch, tty_port_tty_get(&port->port));
+                        handle_sysrq(ch, tty);
                         port->sysrq = 0;
                         return 1;
                 }