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USB: serial: keyspan_pda: refactor write-room handling

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Add helper to retrieve the available device transfer-buffer space.

Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Johan Hovold 2020-10-25 18:45:53 +01:00
parent 320f9028c7
commit 79fe6826a5
1 changed files with 51 additions and 64 deletions
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115
drivers/usb/serial/keyspan_pda.c
View File

@ -98,6 +98,42 @@ static const struct usb_device_id id_table_fake_xircom[] = {
}; };
#endif #endif
static int keyspan_pda_get_write_room(struct keyspan_pda_private *priv)
{
struct usb_serial_port *port = priv->port;
struct usb_serial *serial = priv->serial;
u8 *room;
int rc;
room = kmalloc(1, GFP_KERNEL);
if (!room)
return -ENOMEM;
rc = usb_control_msg(serial->dev,
usb_rcvctrlpipe(serial->dev, 0),
6, /* write_room */
USB_TYPE_VENDOR | USB_RECIP_INTERFACE
| USB_DIR_IN,
0, /* value: 0 means "remaining room" */
0, /* index */
room,
1,
2000);
if (rc != 1) {
if (rc >= 0)
rc = -EIO;
dev_dbg(&port->dev, "roomquery failed: %d\n", rc);
goto out_free;
}
dev_dbg(&port->dev, "roomquery says %d\n", *room);
rc = *room;
out_free:
kfree(room);
return rc;
}
static void keyspan_pda_request_unthrottle(struct work_struct *work) static void keyspan_pda_request_unthrottle(struct work_struct *work)
{ {
struct keyspan_pda_private *priv = struct keyspan_pda_private *priv =
@ -436,7 +472,6 @@ static int keyspan_pda_tiocmset(struct tty_struct *tty,
static int keyspan_pda_write(struct tty_struct *tty, static int keyspan_pda_write(struct tty_struct *tty,
struct usb_serial_port *port, const unsigned char *buf, int count) struct usb_serial_port *port, const unsigned char *buf, int count)
{ {
struct usb_serial *serial = port->serial;
int request_unthrottle = 0; int request_unthrottle = 0;
int rc = 0; int rc = 0;
struct keyspan_pda_private *priv; struct keyspan_pda_private *priv;
@ -479,38 +514,11 @@ static int keyspan_pda_write(struct tty_struct *tty,
device how much room it really has. This is done only on device how much room it really has. This is done only on
scheduler time, since usb_control_msg() sleeps. */ scheduler time, since usb_control_msg() sleeps. */
if (count > priv->tx_room && !in_interrupt()) { if (count > priv->tx_room && !in_interrupt()) {
u8 *room; rc = keyspan_pda_get_write_room(priv);
if (rc < 0)
goto exit;
room = kmalloc(1, GFP_KERNEL); priv->tx_room = rc;
if (!room) {
rc = -ENOMEM;
goto exit;
}
rc = usb_control_msg(serial->dev,
usb_rcvctrlpipe(serial->dev, 0),
6, /* write_room */
USB_TYPE_VENDOR | USB_RECIP_INTERFACE
| USB_DIR_IN,
0, /* value: 0 means "remaining room" */
0, /* index */
room,
1,
2000);
if (rc > 0) {
dev_dbg(&port->dev, "roomquery says %d\n", *room);
priv->tx_room = *room;
}
kfree(room);
if (rc < 0) {
dev_dbg(&port->dev, "roomquery failed\n");
goto exit;
}
if (rc == 0) {
dev_dbg(&port->dev, "roomquery returned 0 bytes\n");
rc = -EIO; /* device didn't return any data */
goto exit;
}
} }
if (count >= priv->tx_room) { if (count >= priv->tx_room) {
@ -614,48 +622,27 @@ static void keyspan_pda_dtr_rts(struct usb_serial_port *port, int on)
static int keyspan_pda_open(struct tty_struct *tty, static int keyspan_pda_open(struct tty_struct *tty,
struct usb_serial_port *port) struct usb_serial_port *port)
{ {
struct usb_serial *serial = port->serial; struct keyspan_pda_private *priv = usb_get_serial_port_data(port);
u8 *room; int rc;
int rc = 0;
struct keyspan_pda_private *priv;
/* find out how much room is in the Tx ring */ /* find out how much room is in the Tx ring */
room = kmalloc(1, GFP_KERNEL); rc = keyspan_pda_get_write_room(priv);
if (!room) if (rc < 0)
return -ENOMEM; return rc;
rc = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), priv->tx_room = rc;
6, /* write_room */ priv->tx_throttled = rc ? 0 : 1;
USB_TYPE_VENDOR | USB_RECIP_INTERFACE
| USB_DIR_IN,
0, /* value */
0, /* index */
room,
1,
2000);
if (rc < 0) {
dev_dbg(&port->dev, "%s - roomquery failed\n", __func__);
goto error;
}
if (rc == 0) {
dev_dbg(&port->dev, "%s - roomquery returned 0 bytes\n", __func__);
rc = -EIO;
goto error;
}
priv = usb_get_serial_port_data(port);
priv->tx_room = *room;
priv->tx_throttled = *room ? 0 : 1;
/*Start reading from the device*/ /*Start reading from the device*/
rc = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); rc = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
if (rc) { if (rc) {
dev_dbg(&port->dev, "%s - usb_submit_urb(read int) failed\n", __func__); dev_dbg(&port->dev, "%s - usb_submit_urb(read int) failed\n", __func__);
goto error; return rc;
} }
error:
kfree(room); return 0;
return rc;
} }
static void keyspan_pda_close(struct usb_serial_port *port) static void keyspan_pda_close(struct usb_serial_port *port)
{ {
struct keyspan_pda_private *priv = usb_get_serial_port_data(port); struct keyspan_pda_private *priv = usb_get_serial_port_data(port);