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>
diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
index cea5603..cac6663 100644
--- a/drivers/tty/n_hdlc.c
+++ b/drivers/tty/n_hdlc.c
@@ -188,8 +188,8 @@
poll_table *wait);
static int n_hdlc_tty_open(struct tty_struct *tty);
static void n_hdlc_tty_close(struct tty_struct *tty);
-static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *cp,
- char *fp, int count);
+static unsigned int n_hdlc_tty_receive(struct tty_struct *tty,
+ const __u8 *cp, char *fp, int count);
static void n_hdlc_tty_wakeup(struct tty_struct *tty);
#define bset(p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f)))
@@ -509,8 +509,8 @@
* Called by tty low level driver when receive data is available. Data is
* interpreted as one HDLC frame.
*/
-static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,
- char *flags, int count)
+static unsigned int n_hdlc_tty_receive(struct tty_struct *tty,
+ const __u8 *data, char *flags, int count)
{
register struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
register struct n_hdlc_buf *buf;
@@ -521,20 +521,20 @@
/* This can happen if stuff comes in on the backup tty */
if (!n_hdlc || tty != n_hdlc->tty)
- return;
+ return -ENODEV;
/* verify line is using HDLC discipline */
if (n_hdlc->magic != HDLC_MAGIC) {
printk("%s(%d) line not using HDLC discipline\n",
__FILE__,__LINE__);
- return;
+ return -EINVAL;
}
if ( count>maxframe ) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d) rx count>maxframesize, data discarded\n",
__FILE__,__LINE__);
- return;
+ return -EINVAL;
}
/* get a free HDLC buffer */
@@ -550,7 +550,7 @@
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d) no more rx buffers, data discarded\n",
__FILE__,__LINE__);
- return;
+ return -EINVAL;
}
/* copy received data to HDLC buffer */
@@ -565,6 +565,8 @@
if (n_hdlc->tty->fasync != NULL)
kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN);
+ return count;
+
} /* end of n_hdlc_tty_receive() */
/**