1 files changed, 66 insertions, 35 deletions

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index b362039792b3..1b51d3187a95 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -1,5 +1,5 @@
 /*
- * USB Skeleton driver - 2.0
+ * USB Skeleton driver - 2.2
  *
  * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
  *
@@ -7,9 +7,8 @@
  *      modify it under the terms of the GNU General Public License as
  *      published by the Free Software Foundation, version 2.
  *
- * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c 
- * but has been rewritten to be easy to read and use, as no locks are now
- * needed anymore.
+ * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
+ * but has been rewritten to be easier to read and use.
  *
  */
 
@@ -21,6 +20,7 @@
 #include <linux/kref.h>
 #include <asm/uaccess.h>
 #include <linux/usb.h>
+#include <linux/mutex.h>
 
 
 /* Define these values to match your devices */
@@ -32,38 +32,39 @@ static struct usb_device_id skel_table [] = {
         { USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
         { }                                     /* Terminating entry */
 };
-MODULE_DEVICE_TABLE (usb, skel_table);
+MODULE_DEVICE_TABLE(usb, skel_table);
 
 
 /* Get a minor range for your devices from the usb maintainer */
 #define USB_SKEL_MINOR_BASE     192
 
 /* our private defines. if this grows any larger, use your own .h file */
-#define MAX_TRANSFER            ( PAGE_SIZE - 512 )
+#define MAX_TRANSFER            (PAGE_SIZE - 512)
 #define WRITES_IN_FLIGHT        8
 
 /* Structure to hold all of our device specific stuff */
 struct usb_skel {
-        struct usb_device *     udev;                   /* the usb device for this device */
-        struct usb_interface *  interface;              /* the interface for this device */
+        struct usb_device       *dev;                   /* the usb device for this device */
+        struct usb_interface    *interface;             /* the interface for this device */
         struct semaphore        limit_sem;              /* limiting the number of writes in progress */
-        unsigned char *         bulk_in_buffer;         /* the buffer to receive data */
+        unsigned char           *bulk_in_buffer;        /* the buffer to receive data */
         size_t                  bulk_in_size;           /* the size of the receive buffer */
         __u8                    bulk_in_endpointAddr;   /* the address of the bulk in endpoint */
         __u8                    bulk_out_endpointAddr;  /* the address of the bulk out endpoint */
         struct kref             kref;
+        struct mutex            io_mutex;               /* synchronize I/O with disconnect */
 };
 #define to_skel_dev(d) container_of(d, struct usb_skel, kref)
 
 static struct usb_driver skel_driver;
 
 static void skel_delete(struct kref *kref)
-{       
+{
         struct usb_skel *dev = to_skel_dev(kref);
 
         usb_put_dev(dev->udev);
-        kfree (dev->bulk_in_buffer);
-        kfree (dev);
+        kfree(dev->bulk_in_buffer);
+        kfree(dev);
 }
 
 static int skel_open(struct inode *inode, struct file *file)
@@ -89,6 +90,11 @@ static int skel_open(struct inode *inode, struct file *file)
                 goto exit;
         }
 
+        /* prevent the device from being autosuspended */
+        retval = usb_autopm_get_interface(interface);
+        if (retval)
+                goto exit;
+
         /* increment our usage count for the device */
         kref_get(&dev->kref);
 
@@ -107,6 +113,12 @@ static int skel_release(struct inode *inode, struct file *file)
         if (dev == NULL)
                 return -ENODEV;
 
+        /* allow the device to be autosuspended */
+        mutex_lock(&dev->io_mutex);
+        if (dev->interface)
+                usb_autopm_put_interface(dev->interface);
+        mutex_unlock(&dev->io_mutex);
+
         /* decrement the count on our device */
         kref_put(&dev->kref, skel_delete);
         return 0;
@@ -115,11 +127,17 @@ static int skel_release(struct inode *inode, struct file *file)
 static ssize_t skel_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
 {
         struct usb_skel *dev;
-        int retval = 0;
+        int retval;
         int bytes_read;
 
         dev = (struct usb_skel *)file->private_data;
-        
+
+        mutex_lock(&dev->io_mutex);
+        if (!dev->interface) {          /* disconnect() was called */
+                retval = -ENODEV;
+                goto exit;
+        }
+
         /* do a blocking bulk read to get data from the device */
         retval = usb_bulk_msg(dev->udev,
                               usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
@@ -135,6 +153,8 @@ static ssize_t skel_read(struct file *file, char *buffer, size_t count, loff_t *
                         retval = bytes_read;
         }
 
+exit:
+        mutex_unlock(&dev->io_mutex);
         return retval;
 }
 
@@ -145,16 +165,16 @@ static void skel_write_bulk_callback(struct urb *urb, struct pt_regs *regs)
         dev = (struct usb_skel *)urb->context;
 
         /* sync/async unlink faults aren't errors */
-        if (urb->status && 
-            !(urb->status == -ENOENT || 
+        if (urb->status &&
+            !(urb->status == -ENOENT ||
               urb->status == -ECONNRESET ||
               urb->status == -ESHUTDOWN)) {
-                dbg("%s - nonzero write bulk status received: %d",
+                err("%s - nonzero write bulk status received: %d",
                     __FUNCTION__, urb->status);
         }
 
         /* free up our allocated buffer */
-        usb_buffer_free(urb->dev, urb->transfer_buffer_length, 
+        usb_buffer_free(urb->dev, urb->transfer_buffer_length,
                         urb->transfer_buffer, urb->transfer_dma);
         up(&dev->limit_sem);
 }
@@ -179,6 +199,12 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou
                 goto exit;
         }
 
+        mutex_lock(&dev->io_mutex);
+        if (!dev->interface) {          /* disconnect() was called */
+                retval = -ENODEV;
+                goto error;
+        }
+
         /* create a urb, and a buffer for it, and copy the data to the urb */
         urb = usb_alloc_urb(0, GFP_KERNEL);
         if (!urb) {
@@ -213,17 +239,22 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou
         /* release our reference to this urb, the USB core will eventually free it entirely */
         usb_free_urb(urb);
 
-exit:
+        mutex_unlock(&dev->io_mutex);
         return writesize;
 
 error:
-        usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
-        usb_free_urb(urb);
+        if (urb) {
+                usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
+                usb_free_urb(urb);
+        }
+        mutex_unlock(&dev->io_mutex);
         up(&dev->limit_sem);
+
+exit:
         return retval;
 }
 
-static struct file_operations skel_fops = {
+static const struct file_operations skel_fops = {
         .owner =        THIS_MODULE,
         .read =         skel_read,
         .write =        skel_write,
@@ -231,7 +262,7 @@ static struct file_operations skel_fops = {
         .release =      skel_release,
 };
 
-/* 
+/*
  * usb class driver info in order to get a minor number from the usb core,
  * and to have the device registered with the driver core
  */
@@ -243,7 +274,7 @@ static struct usb_class_driver skel_class = {
 
 static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id)
 {
-        struct usb_skel *dev = NULL;
+        struct usb_skel *dev;
         struct usb_host_interface *iface_desc;
         struct usb_endpoint_descriptor *endpoint;
         size_t buffer_size;
@@ -252,12 +283,13 @@ static int skel_probe(struct usb_interface *interface, const struct usb_device_i
 
         /* allocate memory for our device state and initialize it */
         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
-        if (dev == NULL) {
+        if (!dev) {
                 err("Out of memory");
                 goto error;
         }
         kref_init(&dev->kref);
         sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
+        mutex_init(&dev->io_mutex);
 
         dev->udev = usb_get_dev(interface_to_usbdev(interface));
         dev->interface = interface;
@@ -269,10 +301,7 @@ static int skel_probe(struct usb_interface *interface, const struct usb_device_i
                 endpoint = &iface_desc->endpoint[i].desc;
 
                 if (!dev->bulk_in_endpointAddr &&
-                    ((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
-                                        == USB_DIR_IN) &&
-                    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
-                                        == USB_ENDPOINT_XFER_BULK)) {
+                    usb_endpoint_is_bulk_in(endpoint)) {
                         /* we found a bulk in endpoint */
                         buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
                         dev->bulk_in_size = buffer_size;
@@ -285,10 +314,7 @@ static int skel_probe(struct usb_interface *interface, const struct usb_device_i
                 }
 
                 if (!dev->bulk_out_endpointAddr &&
-                    ((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
-                                        == USB_DIR_OUT) &&
-                    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
-                                        == USB_ENDPOINT_XFER_BULK)) {
+                    usb_endpoint_is_bulk_out(endpoint)) {
                         /* we found a bulk out endpoint */
                         dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
                 }
@@ -334,6 +360,11 @@ static void skel_disconnect(struct usb_interface *interface)
         /* give back our minor */
         usb_deregister_dev(interface, &skel_class);
 
+        /* prevent more I/O from starting */
+        mutex_lock(&dev->io_mutex);
+        dev->interface = NULL;
+        mutex_unlock(&dev->io_mutex);
+
         unlock_kernel();
 
         /* decrement our usage count */
@@ -367,7 +398,7 @@ static void __exit usb_skel_exit(void)
         usb_deregister(&skel_driver);
 }
 
-module_init (usb_skel_init);
-module_exit (usb_skel_exit);
+module_init(usb_skel_init);
+module_exit(usb_skel_exit);
 
 MODULE_LICENSE("GPL");