tty: make tty_operations::write_room return uint

Line disciplines expect a positive value or zero returned from
tty->ops->write_room (invoked by tty_write_room). So make this
assumption explicit by using unsigned int as a return value. Both of
tty->ops->write_room and tty_write_room.

Signed-off-by: Jiri Slaby <[email protected]>
Acked-by: Laurentiu Tudor <[email protected]>
Acked-by: Alex Elder <[email protected]>
Acked-by: Max Filippov <[email protected]> # xtensa
Acked-by: David Sterba <[email protected]>
Acked-By: Anton Ivanov <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Ivan Kokshaysky <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Jeff Dike <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Chris Zankel <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Samuel Iglesias Gonsalvez <[email protected]>
Cc: Jens Taprogge <[email protected]>
Cc: Karsten Keil <[email protected]>
Cc: Scott Branden <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: David Lin <[email protected]>
Cc: Johan Hovold <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Shawn Guo <[email protected]>
Cc: Sascha Hauer <[email protected]>
Cc: Oliver Neukum <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: Mathias Nyman <[email protected]>
Cc: Marcel Holtmann <[email protected]>
Cc: Johan Hedberg <[email protected]>
Cc: Luiz Augusto von Dentz <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/tty/moxa.c b/drivers/tty/moxa.c
index 847ad3dac107..e4fe9315de29 100644
--- a/drivers/tty/moxa.c
+++ b/drivers/tty/moxa.c
@@ -188,7 +188,7 @@ module_param(ttymajor, int, 0);
 static int moxa_open(struct tty_struct *, struct file *);
 static void moxa_close(struct tty_struct *, struct file *);
 static int moxa_write(struct tty_struct *, const unsigned char *, int);
-static int moxa_write_room(struct tty_struct *);
+static unsigned int moxa_write_room(struct tty_struct *);
 static void moxa_flush_buffer(struct tty_struct *);
 static int moxa_chars_in_buffer(struct tty_struct *);
 static void moxa_set_termios(struct tty_struct *, struct ktermios *);
@@ -218,7 +218,7 @@ static int MoxaPortWriteData(struct tty_struct *, const unsigned char *, int);
 static int MoxaPortReadData(struct moxa_port *);
 static int MoxaPortTxQueue(struct moxa_port *);
 static int MoxaPortRxQueue(struct moxa_port *);
-static int MoxaPortTxFree(struct moxa_port *);
+static unsigned int MoxaPortTxFree(struct moxa_port *);
 static void MoxaPortTxDisable(struct moxa_port *);
 static void MoxaPortTxEnable(struct moxa_port *);
 static int moxa_get_serial_info(struct tty_struct *, struct serial_struct *);
@@ -1217,7 +1217,7 @@ static int moxa_write(struct tty_struct *tty,
 	return len;
 }
 
-static int moxa_write_room(struct tty_struct *tty)
+static unsigned int moxa_write_room(struct tty_struct *tty)
 {
 	struct moxa_port *ch;
 
@@ -1992,7 +1992,7 @@ static int MoxaPortTxQueue(struct moxa_port *port)
 	return (wptr - rptr) & mask;
 }
 
-static int MoxaPortTxFree(struct moxa_port *port)
+static unsigned int MoxaPortTxFree(struct moxa_port *port)
 {
 	void __iomem *ofsAddr = port->tableAddr;
 	u16 rptr, wptr, mask;