USB: oti6858: use kfifo to implement write buffering

Kill custom fifo implementation.

Use private write fifo to minimise changes to lock handling.

Compile-only tested.

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

diff --git a/drivers/usb/serial/oti6858.c b/drivers/usb/serial/oti6858.c
index 525d852..a65be37 100644 (file)
--- a/drivers/usb/serial/oti6858.c
+++ b/drivers/usb/serial/oti6858.c
@@ -51,12 +51,13 @@
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
 #include <linux/uaccess.h>
+#include <linux/kfifo.h>
 #include "oti6858.h"
 
 #define OTI6858_DESCRIPTION \
        "Ours Technology Inc. OTi-6858 USB to serial adapter driver"
 #define OTI6858_AUTHOR "Tomasz Michal Lukaszewski <FIXME@FIXME>"
-#define OTI6858_VERSION "0.1"
+#define OTI6858_VERSION "0.2"
 
 static const struct usb_device_id id_table[] = {
        { USB_DEVICE(OTI6858_VENDOR_ID, OTI6858_PRODUCT_ID) },
@@ -75,17 +76,7 @@ static struct usb_driver oti6858_driver = {
 
 static int debug;
 
-
-/* buffering code, copied from pl2303 driver */
-#define PL2303_BUF_SIZE                1024
-#define PL2303_TMP_BUF_SIZE    1024
-
-struct oti6858_buf {
-       unsigned int    buf_size;
-       char            *buf_buf;
-       char            *buf_get;
-       char            *buf_put;
-};
+#define OTI6858_FIFO_SIZE              1024
 
 /* requests */
 #define        OTI6858_REQ_GET_STATUS          (USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
@@ -161,18 +152,6 @@ static int oti6858_tiocmset(struct tty_struct *tty, struct file *file,
 static int oti6858_startup(struct usb_serial *serial);
 static void oti6858_release(struct usb_serial *serial);
 
-/* functions operating on buffers */
-static struct oti6858_buf *oti6858_buf_alloc(unsigned int size);
-static void oti6858_buf_free(struct oti6858_buf *pb);
-static void oti6858_buf_clear(struct oti6858_buf *pb);
-static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb);
-static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb);
-static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
-                                       unsigned int count);
-static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
-                                       unsigned int count);
-
-
 /* device info */
 static struct usb_serial_driver oti6858_device = {
        .driver = {
@@ -201,7 +180,7 @@ static struct usb_serial_driver oti6858_device = {
 struct oti6858_private {
        spinlock_t lock;
 
-       struct oti6858_buf *buf;
+       struct kfifo write_fifo;
        struct oti6858_control_pkt status;
 
        struct {
@@ -315,7 +294,7 @@ static void send_data(struct work_struct *work)
        }
        priv->flags.write_urb_in_use = 1;
 
-       count = oti6858_buf_data_avail(priv->buf);
+       count = kfifo_len(&priv->write_fifo);
        spin_unlock_irqrestore(&priv->lock, flags);
        if (count > port->bulk_out_size)
                count = port->bulk_out_size;
@@ -350,10 +329,9 @@ static void send_data(struct work_struct *work)
                return;
        }
 
-       spin_lock_irqsave(&priv->lock, flags);
-       oti6858_buf_get(priv->buf, port->write_urb->transfer_buffer, count);
-       spin_unlock_irqrestore(&priv->lock, flags);
-
+       count = kfifo_out_locked(&priv->write_fifo,
+                                       port->write_urb->transfer_buffer,
+                                       count, &priv->lock);
        port->write_urb->transfer_buffer_length = count;
        port->write_urb->dev = port->serial->dev;
        result = usb_submit_urb(port->write_urb, GFP_NOIO);
@@ -376,8 +354,8 @@ static int oti6858_startup(struct usb_serial *serial)
                priv = kzalloc(sizeof(struct oti6858_private), GFP_KERNEL);
                if (!priv)
                        break;
-               priv->buf = oti6858_buf_alloc(PL2303_BUF_SIZE);
-               if (priv->buf == NULL) {
+               if (kfifo_alloc(&priv->write_fifo, OTI6858_FIFO_SIZE,
+                                                               GFP_KERNEL)) {
                        kfree(priv);
                        break;
                }
@@ -397,7 +375,7 @@ static int oti6858_startup(struct usb_serial *serial)
 
        for (--i; i >= 0; --i) {
                priv = usb_get_serial_port_data(serial->port[i]);
-               oti6858_buf_free(priv->buf);
+               kfifo_free(&priv->write_fifo);
                kfree(priv);
                usb_set_serial_port_data(serial->port[i], NULL);
        }
@@ -408,16 +386,13 @@ static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
                        const unsigned char *buf, int count)
 {
        struct oti6858_private *priv = usb_get_serial_port_data(port);
-       unsigned long flags;
 
        dbg("%s(port = %d, count = %d)", __func__, port->number, count);
 
        if (!count)
                return count;
 
-       spin_lock_irqsave(&priv->lock, flags);
-       count = oti6858_buf_put(priv->buf, buf, count);
-       spin_unlock_irqrestore(&priv->lock, flags);
+       count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);
 
        return count;
 }
@@ -432,7 +407,7 @@ static int oti6858_write_room(struct tty_struct *tty)
        dbg("%s(port = %d)", __func__, port->number);
 
        spin_lock_irqsave(&priv->lock, flags);
-       room = oti6858_buf_space_avail(priv->buf);
+       room = kfifo_avail(&priv->write_fifo);
        spin_unlock_irqrestore(&priv->lock, flags);
 
        return room;
@@ -448,7 +423,7 @@ static int oti6858_chars_in_buffer(struct tty_struct *tty)
        dbg("%s(port = %d)", __func__, port->number);
 
        spin_lock_irqsave(&priv->lock, flags);
-       chars = oti6858_buf_data_avail(priv->buf);
+       chars = kfifo_len(&priv->write_fifo);
        spin_unlock_irqrestore(&priv->lock, flags);
 
        return chars;
@@ -642,7 +617,7 @@ static void oti6858_close(struct usb_serial_port *port)
 
        spin_lock_irqsave(&priv->lock, flags);
        /* clear out any remaining data in the buffer */
-       oti6858_buf_clear(priv->buf);
+       kfifo_reset_out(&priv->write_fifo);
        spin_unlock_irqrestore(&priv->lock, flags);
 
        dbg("%s(): after buf_clear()", __func__);
@@ -793,7 +768,7 @@ static void oti6858_release(struct usb_serial *serial)
        for (i = 0; i < serial->num_ports; ++i) {
                priv = usb_get_serial_port_data(serial->port[i]);
                if (priv) {
-                       oti6858_buf_free(priv->buf);
+                       kfifo_free(&priv->write_fifo);
                        kfree(priv);
                }
        }
@@ -892,7 +867,7 @@ static void oti6858_read_int_callback(struct urb *urb)
 
                spin_lock_irqsave(&priv->lock, flags);
                if (priv->flags.write_urb_in_use == 0
-                               && oti6858_buf_data_avail(priv->buf) != 0) {
+                               && kfifo_len(&priv->write_fifo) != 0) {
                        schedule_delayed_work(&priv->delayed_write_work, 0);
                        resubmit = 0;
                }
@@ -1014,165 +989,6 @@ static void oti6858_write_bulk_callback(struct urb *urb)
        }
 }
 
-
-/*
- * oti6858_buf_alloc
- *
- * Allocate a circular buffer and all associated memory.
- */
-static struct oti6858_buf *oti6858_buf_alloc(unsigned int size)
-{
-       struct oti6858_buf *pb;
-
-       if (size == 0)
-               return NULL;
-
-       pb = kmalloc(sizeof(struct oti6858_buf), GFP_KERNEL);
-       if (pb == NULL)
-               return NULL;
-
-       pb->buf_buf = kmalloc(size, GFP_KERNEL);
-       if (pb->buf_buf == NULL) {
-               kfree(pb);
-               return NULL;
-       }
-
-       pb->buf_size = size;
-       pb->buf_get = pb->buf_put = pb->buf_buf;
-
-       return pb;
-}
-
-/*
- * oti6858_buf_free
- *
- * Free the buffer and all associated memory.
- */
-static void oti6858_buf_free(struct oti6858_buf *pb)
-{
-       if (pb) {
-               kfree(pb->buf_buf);
-               kfree(pb);
-       }
-}
-
-/*
- * oti6858_buf_clear
- *
- * Clear out all data in the circular buffer.
- */
-static void oti6858_buf_clear(struct oti6858_buf *pb)
-{
-       if (pb != NULL) {
-               /* equivalent to a get of all data available */
-               pb->buf_get = pb->buf_put;
-       }
-}
-
-/*
- * oti6858_buf_data_avail
- *
- * Return the number of bytes of data available in the circular
- * buffer.
- */
-static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb)
-{
-       if (pb == NULL)
-               return 0;
-       return (pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size;
-}
-
-/*
- * oti6858_buf_space_avail
- *
- * Return the number of bytes of space available in the circular
- * buffer.
- */
-static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb)
-{
-       if (pb == NULL)
-               return 0;
-       return (pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size;
-}
-
-/*
- * oti6858_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 oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
-                                       unsigned int count)
-{
-       unsigned int len;
-
-       if (pb == NULL)
-               return 0;
-
-       len  = oti6858_buf_space_avail(pb);
-       if (count > len)
-               count = len;
-
-       if (count == 0)
-               return 0;
-
-       len = pb->buf_buf + pb->buf_size - pb->buf_put;
-       if (count > len) {
-               memcpy(pb->buf_put, buf, len);
-               memcpy(pb->buf_buf, buf+len, count - len);
-               pb->buf_put = pb->buf_buf + count - len;
-       } else {
-               memcpy(pb->buf_put, buf, count);
-               if (count < len)
-                       pb->buf_put += count;
-               else /* count == len */
-                       pb->buf_put = pb->buf_buf;
-       }
-
-       return count;
-}
-
-/*
- * oti6858_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 oti6858_buf_get(struct oti6858_buf *pb, char *buf,
-                                       unsigned int count)
-{
-       unsigned int len;
-
-       if (pb == NULL)
-               return 0;
-
-       len = oti6858_buf_data_avail(pb);
-       if (count > len)
-               count = len;
-
-       if (count == 0)
-               return 0;
-
-       len = pb->buf_buf + pb->buf_size - pb->buf_get;
-       if (count > len) {
-               memcpy(buf, pb->buf_get, len);
-               memcpy(buf+len, pb->buf_buf, count - len);
-               pb->buf_get = pb->buf_buf + count - len;
-       } else {
-               memcpy(buf, pb->buf_get, count);
-               if (count < len)
-                       pb->buf_get += count;
-               else /* count == len */
-                       pb->buf_get = pb->buf_buf;
-       }
-
-       return count;
-}
-
 /* module description and (de)initialization */
 
 static int __init oti6858_init(void)