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/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
index ff7dc08..5b07792 100644
--- a/include/linux/tty_ldisc.h
+++ b/include/linux/tty_ldisc.h
@@ -76,7 +76,7 @@
* tty device. It is solely the responsibility of the line
* discipline to handle poll requests.
*
- * void (*receive_buf)(struct tty_struct *, const unsigned char *cp,
+ * unsigned int (*receive_buf)(struct tty_struct *, const unsigned char *cp,
* char *fp, int count);
*
* This function is called by the low-level tty driver to send
@@ -84,7 +84,8 @@
* processing. <cp> is a pointer to the buffer of input
* character received by the device. <fp> is a pointer to a
* pointer of flag bytes which indicate whether a character was
- * received with a parity error, etc.
+ * received with a parity error, etc. Returns the amount of bytes
+ * received.
*
* void (*write_wakeup)(struct tty_struct *);
*
@@ -140,8 +141,8 @@
/*
* The following routines are called from below.
*/
- void (*receive_buf)(struct tty_struct *, const unsigned char *cp,
- char *fp, int count);
+ unsigned int (*receive_buf)(struct tty_struct *,
+ const unsigned char *cp, char *fp, int count);
void (*write_wakeup)(struct tty_struct *);
void (*dcd_change)(struct tty_struct *, unsigned int,
struct pps_event_time *);