USB: tty: Prune uses of tty_request_room in the USB layer

We have lots of callers that do not need to do this in the first place.
Remove the calls as they both cost CPU and for big buffers can mess up the
multi-page allocation avoidance.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 11 deletions

diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index 3b6348414c47..381722858424 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -1658,7 +1658,6 @@ static int digi_read_inb_callback(struct urb *urb)
         int port_status = ((unsigned char *)urb->transfer_buffer)[2];
         unsigned char *data = ((unsigned char *)urb->transfer_buffer) + 3;
         int flag, throttled;
-        int i;
         int status = urb->status;
 
         /* do not process callbacks on closed ports */
@@ -1705,17 +1704,9 @@ static int digi_read_inb_callback(struct urb *urb)
 
                 /* data length is len-1 (one byte of len is port_status) */
                 --len;
-
-                len = tty_buffer_request_room(tty, len);
                 if (len > 0) {
-                        /* Hot path */
-                        if (flag == TTY_NORMAL)
-                                tty_insert_flip_string(tty, data, len);
-                        else {
-                                for (i = 0; i < len; i++)
-                                        tty_insert_flip_char(tty,
-                                                                data[i], flag);
-                        }
+                        tty_insert_flip_string_fixed_flag(tty, data, len,
+                                                                        flag);
                         tty_flip_buffer_push(tty);
                 }
         }