tty: make receive_buf() return the amout of bytes received

it makes it simpler to keep track of the amount of
bytes received and simplifies how flush_to_ldisc counts
the remaining bytes. It also fixes a bug of lost bytes
on n_tty when flushing too many bytes via the USB
serial gadget driver.

Tested-by: Stefan Bigler <stefan.bigler@keymile.com>
Tested-by: Toby Gray <toby.gray@realvnc.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 1 insertions, 2 deletions

diff --git a/drivers/tty/vt/selection.c b/drivers/tty/vt/selection.c
index fb864e7fcd1..67b1d0d7c8a 100644
--- a/drivers/tty/vt/selection.c
+++ b/drivers/tty/vt/selection.c
@@ -332,8 +332,7 @@ int paste_selection(struct tty_struct *tty)
                         continue;
                 }
                 count = sel_buffer_lth - pasted;
-                count = min(count, tty->receive_room);
-                tty->ldisc->ops->receive_buf(tty, sel_buffer + pasted,
+                count = tty->ldisc->ops->receive_buf(tty, sel_buffer + pasted,
                                                                 NULL, count);
                 pasted += count;
         }