USB: io_ti: use kfifo to implement write buffering

Kill custom fifo implementation.

Compile-only tested.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/io_ti.c

@@ -36,6 +36,7 @@
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
 #include <linux/serial.h>
+#include <linux/kfifo.h>
 #include <linux/ioctl.h>
 #include <linux/firmware.h>
 #include <linux/uaccess.h>
@@ -83,14 +84,6 @@ struct product_info {
 	__u8	hardware_type;		/* Type of hardware */
 } __attribute__((packed));
 
-/* circular buffer */
-struct edge_buf {
-	unsigned int	buf_size;
-	char		*buf_buf;
-	char		*buf_get;
-	char		*buf_put;
-};
-
 struct edgeport_port {
 	__u16 uart_base;
 	__u16 dma_address;
@@ -114,7 +107,7 @@ struct edgeport_port {
 	spinlock_t ep_lock;
 	int ep_read_urb_state;
 	int ep_write_urb_in_use;
-	struct edge_buf *ep_out_buf;
+	struct kfifo write_fifo;
 };
 
 struct edgeport_serial {
@@ -244,17 +237,6 @@ static void edge_send(struct tty_struct *tty);
 static int edge_create_sysfs_attrs(struct usb_serial_port *port);
 static int edge_remove_sysfs_attrs(struct usb_serial_port *port);
 
-/* circular buffer */
-static struct edge_buf *edge_buf_alloc(unsigned int size);
-static void edge_buf_free(struct edge_buf *eb);
-static void edge_buf_clear(struct edge_buf *eb);
-static unsigned int edge_buf_data_avail(struct edge_buf *eb);
-static unsigned int edge_buf_space_avail(struct edge_buf *eb);
-static unsigned int edge_buf_put(struct edge_buf *eb, const char *buf,
-	unsigned int count);
-static unsigned int edge_buf_get(struct edge_buf *eb, char *buf,
-	unsigned int count);
-
 
 static int ti_vread_sync(struct usb_device *dev, __u8 request,
 				__u16 value, __u16 index, u8 *data, int size)
@@ -585,7 +567,7 @@ static void chase_port(struct edgeport_port *port, unsigned long timeout,
 	add_wait_queue(&tty->write_wait, &wait);
 	for (;;) {
 		set_current_state(TASK_INTERRUPTIBLE);
-		if (edge_buf_data_avail(port->ep_out_buf) == 0
+		if (kfifo_len(&port->write_fifo) == 0
 		|| timeout == 0 || signal_pending(current)
 		|| !usb_get_intfdata(port->port->serial->interface))
 			/* disconnect */
@@ -597,7 +579,7 @@ static void chase_port(struct edgeport_port *port, unsigned long timeout,
 	set_current_state(TASK_RUNNING);
 	remove_wait_queue(&tty->write_wait, &wait);
 	if (flush)
-		edge_buf_clear(port->ep_out_buf);
+		kfifo_reset_out(&port->write_fifo);
 	spin_unlock_irqrestore(&port->ep_lock, flags);
 	tty_kref_put(tty);
 
@@ -2084,7 +2066,6 @@ static int edge_write(struct tty_struct *tty, struct usb_serial_port *port,
 				const unsigned char *data, int count)
 {
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
-	unsigned long flags;
 
 	dbg("%s - port %d", __func__, port->number);
 
@@ -2098,10 +2079,8 @@ static int edge_write(struct tty_struct *tty, struct usb_serial_port *port,
 	if (edge_port->close_pending == 1)
 		return -ENODEV;
 
-	spin_lock_irqsave(&edge_port->ep_lock, flags);
-	count = edge_buf_put(edge_port->ep_out_buf, data, count);
-	spin_unlock_irqrestore(&edge_port->ep_lock, flags);
-
+	count = kfifo_in_locked(&edge_port->write_fifo, data, count,
+							&edge_port->ep_lock);
 	edge_send(tty);
 
 	return count;
@@ -2124,7 +2103,7 @@ static void edge_send(struct tty_struct *tty)
 		return;
 	}
 
-	count = edge_buf_get(edge_port->ep_out_buf,
+	count = kfifo_out(&edge_port->write_fifo,
 				port->write_urb->transfer_buffer,
 				port->bulk_out_size);
 
@@ -2180,7 +2159,7 @@ static int edge_write_room(struct tty_struct *tty)
 		return 0;
 
 	spin_lock_irqsave(&edge_port->ep_lock, flags);
-	room = edge_buf_space_avail(edge_port->ep_out_buf);
+	room = kfifo_avail(&edge_port->write_fifo);
 	spin_unlock_irqrestore(&edge_port->ep_lock, flags);
 
 	dbg("%s - returns %d", __func__, room);
@@ -2202,7 +2181,7 @@ static int edge_chars_in_buffer(struct tty_struct *tty)
 		return 0;
 
 	spin_lock_irqsave(&edge_port->ep_lock, flags);
-	chars = edge_buf_data_avail(edge_port->ep_out_buf);
+	chars = kfifo_len(&edge_port->write_fifo);
 	spin_unlock_irqrestore(&edge_port->ep_lock, flags);
 
 	dbg("%s - returns %d", __func__, chars);
@@ -2659,8 +2638,8 @@ static int edge_startup(struct usb_serial *serial)
 			goto cleanup;
 		}
 		spin_lock_init(&edge_port->ep_lock);
-		edge_port->ep_out_buf = edge_buf_alloc(EDGE_OUT_BUF_SIZE);
-		if (edge_port->ep_out_buf == NULL) {
+		if (kfifo_alloc(&edge_port->write_fifo, EDGE_OUT_BUF_SIZE,
+								GFP_KERNEL)) {
 			dev_err(&serial->dev->dev, "%s - Out of memory\n",
 								__func__);
 			kfree(edge_port);
@@ -2677,7 +2656,7 @@ static int edge_startup(struct usb_serial *serial)
 cleanup:
 	for (--i; i >= 0; --i) {
 		edge_port = usb_get_serial_port_data(serial->port[i]);
-		edge_buf_free(edge_port->ep_out_buf);
+		kfifo_free(&edge_port->write_fifo);
 		kfree(edge_port);
 		usb_set_serial_port_data(serial->port[i], NULL);
 	}
@@ -2708,7 +2687,7 @@ static void edge_release(struct usb_serial *serial)
 
 	for (i = 0; i < serial->num_ports; ++i) {
 		edge_port = usb_get_serial_port_data(serial->port[i]);
-		edge_buf_free(edge_port->ep_out_buf);
+		kfifo_free(&edge_port->write_fifo);
 		kfree(edge_port);
 	}
 	kfree(usb_get_serial_data(serial));
@@ -2758,182 +2737,6 @@ static int edge_remove_sysfs_attrs(struct usb_serial_port *port)
 }
 
 
-/* Circular Buffer */
-
-/*
- * edge_buf_alloc
- *
- * Allocate a circular buffer and all associated memory.
- */
-
-static struct edge_buf *edge_buf_alloc(unsigned int size)
-{
-	struct edge_buf *eb;
-
-
-	if (size == 0)
-		return NULL;
-
-	eb = kmalloc(sizeof(struct edge_buf), GFP_KERNEL);
-	if (eb == NULL)
-		return NULL;
-
-	eb->buf_buf = kmalloc(size, GFP_KERNEL);
-	if (eb->buf_buf == NULL) {
-		kfree(eb);
-		return NULL;
-	}
-
-	eb->buf_size = size;
-	eb->buf_get = eb->buf_put = eb->buf_buf;
-
-	return eb;
-}
-
-
-/*
- * edge_buf_free
- *
- * Free the buffer and all associated memory.
- */
-
-static void edge_buf_free(struct edge_buf *eb)
-{
-	if (eb) {
-		kfree(eb->buf_buf);
-		kfree(eb);
-	}
-}
-
-
-/*
- * edge_buf_clear
- *
- * Clear out all data in the circular buffer.
- */
-
-static void edge_buf_clear(struct edge_buf *eb)
-{
-	if (eb != NULL)
-		eb->buf_get = eb->buf_put;
-	/* equivalent to a get of all data available */
-}
-
-
-/*
- * edge_buf_data_avail
- *
- * Return the number of bytes of data available in the circular
- * buffer.
- */
-
-static unsigned int edge_buf_data_avail(struct edge_buf *eb)
-{
-	if (eb == NULL)
-		return 0;
-	return ((eb->buf_size + eb->buf_put - eb->buf_get) % eb->buf_size);
-}
-
-
-/*
- * edge_buf_space_avail
- *
- * Return the number of bytes of space available in the circular
- * buffer.
- */
-
-static unsigned int edge_buf_space_avail(struct edge_buf *eb)
-{
-	if (eb == NULL)
-		return 0;
-	return ((eb->buf_size + eb->buf_get - eb->buf_put - 1) % eb->buf_size);
-}
-
-
-/*
- * edge_buf_put
- *
- * Copy data data from a user buffer and put it into the circular buffer.
- * Restrict to the amount of space available.
- *
- * Return the number of bytes copied.
- */
-
-static unsigned int edge_buf_put(struct edge_buf *eb, const char *buf,
-	unsigned int count)
-{
-	unsigned int len;
-
-
-	if (eb == NULL)
-		return 0;
-
-	len  = edge_buf_space_avail(eb);
-	if (count > len)
-		count = len;
-
-	if (count == 0)
-		return 0;
-
-	len = eb->buf_buf + eb->buf_size - eb->buf_put;
-	if (count > len) {
-		memcpy(eb->buf_put, buf, len);
-		memcpy(eb->buf_buf, buf+len, count - len);
-		eb->buf_put = eb->buf_buf + count - len;
-	} else {
-		memcpy(eb->buf_put, buf, count);
-		if (count < len)
-			eb->buf_put += count;
-		else /* count == len */
-			eb->buf_put = eb->buf_buf;
-	}
-
-	return count;
-}
-
-
-/*
- * edge_buf_get
- *
- * Get data from the circular buffer and copy to the given buffer.
- * Restrict to the amount of data available.
- *
- * Return the number of bytes copied.
- */
-
-static unsigned int edge_buf_get(struct edge_buf *eb, char *buf,
-	unsigned int count)
-{
-	unsigned int len;
-
-
-	if (eb == NULL)
-		return 0;
-
-	len = edge_buf_data_avail(eb);
-	if (count > len)
-		count = len;
-
-	if (count == 0)
-		return 0;
-
-	len = eb->buf_buf + eb->buf_size - eb->buf_get;
-	if (count > len) {
-		memcpy(buf, eb->buf_get, len);
-		memcpy(buf+len, eb->buf_buf, count - len);
-		eb->buf_get = eb->buf_buf + count - len;
-	} else {
-		memcpy(buf, eb->buf_get, count);
-		if (count < len)
-			eb->buf_get += count;
-		else /* count == len */
-			eb->buf_get = eb->buf_buf;
-	}
-
-	return count;
-}
-
-
 static struct usb_serial_driver edgeport_1port_device = {
 	.driver = {
 		.owner		= THIS_MODULE,