USB: keyspan: fix tty line-status reporting

commit 5d1678a3 upstream.

Fix handling of TTY error flags, which are not bitmasks and must
specifically not be ORed together as this prevents the line discipline
from recognising them.

Also insert null characters when reporting overrun errors as these are
not associated with the received character.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Johan Hovold <johan@kernel.org>
[bwh: Backported to 3.2:
 - s/\&port->port/tty/
 - Adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/usb/serial/keyspan.c

@@ -447,14 +447,19 @@ static void	usa26_indat_callback(struct urb *urb)
 			/* some bytes had errors, every byte has status */
 			dbg("%s - RX error!!!!", __func__);
 			for (i = 0; i + 1 < urb->actual_length; i += 2) {
-				int stat = data[i], flag = 0;
-				if (stat & RXERROR_OVERRUN)
-					flag |= TTY_OVERRUN;
-				if (stat & RXERROR_FRAMING)
-					flag |= TTY_FRAME;
-				if (stat & RXERROR_PARITY)
-					flag |= TTY_PARITY;
+				int stat = data[i];
+				int flag = TTY_NORMAL;
+
+				if (stat & RXERROR_OVERRUN) {
+					tty_insert_flip_char(tty, 0,
+								TTY_OVERRUN);
+				}
 				/* XXX should handle break (0x10) */
+				if (stat & RXERROR_PARITY)
+					flag = TTY_PARITY;
+				else if (stat & RXERROR_FRAMING)
+					flag = TTY_FRAME;
+
 				tty_insert_flip_char(tty, data[i+1], flag);
 			}
 		}
@@ -832,14 +837,19 @@ static void	usa49_indat_callback(struct urb *urb)
 		} else {
 			/* some bytes had errors, every byte has status */
 			for (i = 0; i + 1 < urb->actual_length; i += 2) {
-				int stat = data[i], flag = 0;
-				if (stat & RXERROR_OVERRUN)
-					flag |= TTY_OVERRUN;
-				if (stat & RXERROR_FRAMING)
-					flag |= TTY_FRAME;
-				if (stat & RXERROR_PARITY)
-					flag |= TTY_PARITY;
+				int stat = data[i];
+				int flag = TTY_NORMAL;
+
+				if (stat & RXERROR_OVERRUN) {
+					tty_insert_flip_char(tty, 0,
+								TTY_OVERRUN);
+				}
 				/* XXX should handle break (0x10) */
+				if (stat & RXERROR_PARITY)
+					flag = TTY_PARITY;
+				else if (stat & RXERROR_FRAMING)
+					flag = TTY_FRAME;
+
 				tty_insert_flip_char(tty, data[i+1], flag);
 			}
 		}
@@ -900,14 +910,19 @@ static void usa49wg_indat_callback(struct urb *urb)
 				 * some bytes had errors, every byte has status
 				 */
 				for (x = 0; x + 1 < len; x += 2) {
-					int stat = data[i], flag = 0;
-					if (stat & RXERROR_OVERRUN)
-						flag |= TTY_OVERRUN;
-					if (stat & RXERROR_FRAMING)
-						flag |= TTY_FRAME;
-					if (stat & RXERROR_PARITY)
-						flag |= TTY_PARITY;
+					int stat = data[i];
+					int flag = TTY_NORMAL;
+
+					if (stat & RXERROR_OVERRUN) {
+						tty_insert_flip_char(tty, 0,
+								     TTY_OVERRUN);
+					}
 					/* XXX should handle break (0x10) */
+					if (stat & RXERROR_PARITY)
+						flag = TTY_PARITY;
+					else if (stat & RXERROR_FRAMING)
+						flag = TTY_FRAME;
+
 					tty_insert_flip_char(tty,
 							data[i+1], flag);
 					i += 2;
@@ -978,14 +993,20 @@ static void usa90_indat_callback(struct urb *urb)
 			/* some bytes had errors, every byte has status */
 				dbg("%s - RX error!!!!", __func__);
 				for (i = 0; i + 1 < urb->actual_length; i += 2) {
-					int stat = data[i], flag = 0;
-					if (stat & RXERROR_OVERRUN)
-						flag |= TTY_OVERRUN;
-					if (stat & RXERROR_FRAMING)
-						flag |= TTY_FRAME;
-					if (stat & RXERROR_PARITY)
-						flag |= TTY_PARITY;
+					int stat = data[i];
+					int flag = TTY_NORMAL;
+
+					if (stat & RXERROR_OVERRUN) {
+						tty_insert_flip_char(
+								tty, 0,
+								TTY_OVERRUN);
+					}
 					/* XXX should handle break (0x10) */
+					if (stat & RXERROR_PARITY)
+						flag = TTY_PARITY;
+					else if (stat & RXERROR_FRAMING)
+						flag = TTY_FRAME;
+
 					tty_insert_flip_char(tty, data[i+1],
 									flag);
 				}