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, 9 insertions, 7 deletions

diff --git a/drivers/net/irda/irtty-sir.c b/drivers/net/irda/irtty-sir.c
index 3352b2443e5..035861d8acb 100644
--- a/drivers/net/irda/irtty-sir.c
+++ b/drivers/net/irda/irtty-sir.c
@@ -216,23 +216,23 @@ static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t
  * usbserial:   urb-complete-interrupt / softint
  */
 
-static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
-                              char *fp, int count) 
+static unsigned int irtty_receive_buf(struct tty_struct *tty,
+                const unsigned char *cp, char *fp, int count)
 {
         struct sir_dev *dev;
         struct sirtty_cb *priv = tty->disc_data;
         int     i;
 
-        IRDA_ASSERT(priv != NULL, return;);
-        IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
+        IRDA_ASSERT(priv != NULL, return -ENODEV;);
+        IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -EINVAL;);
 
         if (unlikely(count==0))         /* yes, this happens */
-                return;
+                return 0;
 
         dev = priv->dev;
         if (!dev) {
                 IRDA_WARNING("%s(), not ready yet!\n", __func__);
-                return;
+                return -ENODEV;
         }
 
         for (i = 0; i < count; i++) {
@@ -242,11 +242,13 @@ static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
                 if (fp && *fp++) { 
                         IRDA_DEBUG(0, "Framing or parity error!\n");
                         sirdev_receive(dev, NULL, 0);   /* notify sir_dev (updating stats) */
-                        return;
+                        return -EINVAL;
                 }
         }
 
         sirdev_receive(dev, cp, count);
+
+        return count;
 }
 
 /*