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>
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index c349f79..3a5d57f 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -1307,13 +1307,9 @@
spin_unlock_irqrestore(&priv->lock, flags);
/* process read if there is data other than line status */
- if (tty && (bytes > i)) {
- bytes = tty_buffer_request_room(tty, bytes);
- for (; i < bytes ; ++i) {
- dbg("pushing byte number %d - %d - %c", i, data[i],
- data[i]);
- tty_insert_flip_char(tty, data[i], tty_flag);
- }
+ if (tty && bytes > i) {
+ tty_insert_flip_string_fixed_flag(tty, data + i,
+ bytes - i, tty_flag);
tty_flip_buffer_push(tty);
}