From: Jiri Slaby <jslaby@suse.cz>
Date: Tue, 2 Mar 2021 06:22:14 +0000 (+0100)
Subject: tty: make everyone's write_room return >= 0
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=6bfbfcfc58005ee12d37b56a5e722618ef6bee8f;p=uclinux-h8%2Flinux.git

tty: make everyone's write_room return >= 0

The tty line disciplines don't expect tty_operations::write_room to
return negative values. Fix the five drivers which violate this.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-44-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/gdm724x/gdm_tty.c b/drivers/staging/gdm724x/gdm_tty.c
index 6e813693a766..0ccc8c24e754 100644
--- a/drivers/staging/gdm724x/gdm_tty.c
+++ b/drivers/staging/gdm724x/gdm_tty.c
@@ -188,7 +188,7 @@ static int gdm_tty_write_room(struct tty_struct *tty)
 	struct gdm *gdm = tty->driver_data;
 
 	if (!GDM_TTY_READY(gdm))
-		return -ENODEV;
+		return 0;
 
 	return WRITE_SIZE;
 }
diff --git a/drivers/tty/ipwireless/tty.c b/drivers/tty/ipwireless/tty.c
index 1836746991b5..99bb2f149ff5 100644
--- a/drivers/tty/ipwireless/tty.c
+++ b/drivers/tty/ipwireless/tty.c
@@ -235,10 +235,10 @@ static int ipw_write_room(struct tty_struct *linux_tty)
 
 	/* FIXME: Exactly how is the tty object locked here .. */
 	if (!tty)
-		return -ENODEV;
+		return 0;
 
 	if (!tty->port.count)
-		return -EINVAL;
+		return 0;
 
 	room = IPWIRELESS_TX_QUEUE_SIZE - tty->tx_bytes_queued;
 	if (room < 0)
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index da10e975829f..9e12f9cb1a98 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -3048,7 +3048,7 @@ static int gsmtty_write_room(struct tty_struct *tty)
 {
 	struct gsm_dlci *dlci = tty->driver_data;
 	if (dlci->state == DLCI_CLOSED)
-		return -EINVAL;
+		return 0;
 	return TX_SIZE - kfifo_len(&dlci->fifo);
 }
 
diff --git a/drivers/tty/vcc.c b/drivers/tty/vcc.c
index 3106df98558a..0a3a71e14df4 100644
--- a/drivers/tty/vcc.c
+++ b/drivers/tty/vcc.c
@@ -878,7 +878,7 @@ static int vcc_write_room(struct tty_struct *tty)
 	port = vcc_get_ne(tty->index);
 	if (unlikely(!port)) {
 		pr_err("VCC: write_room: Failed to find VCC port\n");
-		return -ENODEV;
+		return 0;
 	}
 
 	num = VCC_BUFF_LEN - port->chars_in_buffer;
diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index 701dfb32b129..bb3d39307d93 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -1042,7 +1042,7 @@ static int mos7720_write_room(struct tty_struct *tty)
 
 	mos7720_port = usb_get_serial_port_data(port);
 	if (mos7720_port == NULL)
-		return -ENODEV;
+		return 0;
 
 	/* FIXME: Locking */
 	for (i = 0; i < NUM_URBS; ++i) {