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 6e81369..0ccc8c2 100644 (file)
--- 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 1836746..99bb2f1 100644 (file)
--- 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 da10e97..9e12f9c 100644 (file)
--- 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 3106df9..0a3a71e 100644 (file)
--- 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 701dfb3..bb3d393 100644 (file)
--- 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) {