1 files changed, 59 insertions, 29 deletions

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index ce310170829..e24ce312307 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -60,6 +60,7 @@ struct usb_skel {
         __u8                    bulk_in_endpointAddr;   /* the address of the bulk in endpoint */
         __u8                    bulk_out_endpointAddr;  /* the address of the bulk out endpoint */
         int                     errors;                 /* the last request tanked */
+        int                     open_count;             /* count the number of openers */
         bool                    ongoing_read;           /* a read is going on */
         bool                    processed_urb;          /* indicates we haven't processed the urb */
         spinlock_t              err_lock;               /* lock for errors */
@@ -93,8 +94,8 @@ static int skel_open(struct inode *inode, struct file *file)
 
         interface = usb_find_interface(&skel_driver, subminor);
         if (!interface) {
-                pr_err("%s - error, can't find device for minor %d\n",
-                        __func__, subminor);
+                err("%s - error, can't find device for minor %d",
+                     __func__, subminor);
                 retval = -ENODEV;
                 goto exit;
         }
@@ -105,15 +106,33 @@ static int skel_open(struct inode *inode, struct file *file)
                 goto exit;
         }
 
-        retval = usb_autopm_get_interface(interface);
-        if (retval)
-                goto exit;
-
         /* increment our usage count for the device */
         kref_get(&dev->kref);
 
+        /* lock the device to allow correctly handling errors
+         * in resumption */
+        mutex_lock(&dev->io_mutex);
+
+        if (!dev->open_count++) {
+                retval = usb_autopm_get_interface(interface);
+                        if (retval) {
+                                dev->open_count--;
+                                mutex_unlock(&dev->io_mutex);
+                                kref_put(&dev->kref, skel_delete);
+                                goto exit;
+                        }
+        } /* else { //uncomment this block if you want exclusive open
+                retval = -EBUSY;
+                dev->open_count--;
+                mutex_unlock(&dev->io_mutex);
+                kref_put(&dev->kref, skel_delete);
+                goto exit;
+        } */
+        /* prevent the device from being autosuspended */
+
         /* save our object in the file's private structure */
         file->private_data = dev;
+        mutex_unlock(&dev->io_mutex);
 
 exit:
         return retval;
@@ -129,7 +148,7 @@ static int skel_release(struct inode *inode, struct file *file)
 
         /* allow the device to be autosuspended */
         mutex_lock(&dev->io_mutex);
-        if (dev->interface)
+        if (!--dev->open_count && dev->interface)
                 usb_autopm_put_interface(dev->interface);
         mutex_unlock(&dev->io_mutex);
 
@@ -174,9 +193,8 @@ static void skel_read_bulk_callback(struct urb *urb)
                 if (!(urb->status == -ENOENT ||
                     urb->status == -ECONNRESET ||
                     urb->status == -ESHUTDOWN))
-                        dev_err(&dev->interface->dev,
-                                "%s - nonzero write bulk status received: %d\n",
-                                __func__, urb->status);
+                        err("%s - nonzero write bulk status received: %d",
+                            __func__, urb->status);
 
                 dev->errors = urb->status;
         } else {
@@ -209,8 +227,7 @@ static int skel_do_read_io(struct usb_skel *dev, size_t count)
         /* do it */
         rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL);
         if (rv < 0) {
-                dev_err(&dev->interface->dev,
-                        "%s - failed submitting read urb, error %d\n",
+                err("%s - failed submitting read urb, error %d",
                         __func__, rv);
                 dev->bulk_in_filled = 0;
                 rv = (rv == -ENOMEM) ? rv : -EIO;
@@ -361,9 +378,8 @@ static void skel_write_bulk_callback(struct urb *urb)
                 if (!(urb->status == -ENOENT ||
                     urb->status == -ECONNRESET ||
                     urb->status == -ESHUTDOWN))
-                        dev_err(&dev->interface->dev,
-                                "%s - nonzero write bulk status received: %d\n",
-                                __func__, urb->status);
+                        err("%s - nonzero write bulk status received: %d",
+                            __func__, urb->status);
 
                 spin_lock(&dev->err_lock);
                 dev->errors = urb->status;
@@ -457,9 +473,8 @@ static ssize_t skel_write(struct file *file, const char *user_buffer,
         retval = usb_submit_urb(urb, GFP_KERNEL);
         mutex_unlock(&dev->io_mutex);
         if (retval) {
-                dev_err(&dev->interface->dev,
-                        "%s - failed submitting write urb, error %d\n",
-                        __func__, retval);
+                err("%s - failed submitting write urb, error %d", __func__,
+                    retval);
                 goto error_unanchor;
         }
 
@@ -518,7 +533,7 @@ static int skel_probe(struct usb_interface *interface,
         /* allocate memory for our device state and initialize it */
         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
         if (!dev) {
-                dev_err(&interface->dev, "Out of memory\n");
+                err("Out of memory");
                 goto error;
         }
         kref_init(&dev->kref);
@@ -540,19 +555,17 @@ static int skel_probe(struct usb_interface *interface,
                 if (!dev->bulk_in_endpointAddr &&
                     usb_endpoint_is_bulk_in(endpoint)) {
                         /* we found a bulk in endpoint */
-                        buffer_size = usb_endpoint_maxp(endpoint);
+                        buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
                         dev->bulk_in_size = buffer_size;
                         dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
                         dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
                         if (!dev->bulk_in_buffer) {
-                                dev_err(&interface->dev,
-                                        "Could not allocate bulk_in_buffer\n");
+                                err("Could not allocate bulk_in_buffer");
                                 goto error;
                         }
                         dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL);
                         if (!dev->bulk_in_urb) {
-                                dev_err(&interface->dev,
-                                        "Could not allocate bulk_in_urb\n");
+                                err("Could not allocate bulk_in_urb");
                                 goto error;
                         }
                 }
@@ -564,8 +577,7 @@ static int skel_probe(struct usb_interface *interface,
                 }
         }
         if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
-                dev_err(&interface->dev,
-                        "Could not find both bulk-in and bulk-out endpoints\n");
+                err("Could not find both bulk-in and bulk-out endpoints");
                 goto error;
         }
 
@@ -576,8 +588,7 @@ static int skel_probe(struct usb_interface *interface,
         retval = usb_register_dev(interface, &skel_class);
         if (retval) {
                 /* something prevented us from registering this driver */
-                dev_err(&interface->dev,
-                        "Not able to get a minor for this device.\n");
+                err("Not able to get a minor for this device.");
                 usb_set_intfdata(interface, NULL);
                 goto error;
         }
@@ -677,6 +688,25 @@ static struct usb_driver skel_driver = {
         .supports_autosuspend = 1,
 };
 
-module_usb_driver(skel_driver);
+static int __init usb_skel_init(void)
+{
+        int result;
+
+        /* register this driver with the USB subsystem */
+        result = usb_register(&skel_driver);
+        if (result)
+                err("usb_register failed. Error number %d", result);
+
+        return result;
+}
+
+static void __exit usb_skel_exit(void)
+{
+        /* deregister this driver with the USB subsystem */
+        usb_deregister(&skel_driver);
+}
+
+module_init(usb_skel_init);
+module_exit(usb_skel_exit);
 
 MODULE_LICENSE("GPL");