USB: usb-skeleton" use anchors in suspend/resume handling

use anchors in suspend/resume handling

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 1b1e669..59973ae 100644 (file)
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -57,6 +57,7 @@ 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 */
        spinlock_t              err_lock;               /* lock for errors */
        struct kref             kref;
        struct mutex            io_mutex;               /* synchronize I/O with disconnect */
@@ -101,12 +102,26 @@ static int skel_open(struct inode *inode, struct file *file)
        /* increment our usage count for the device */
        kref_get(&dev->kref);
 
-       /* prevent the device from being autosuspended */
-       retval = usb_autopm_get_interface(interface);
-       if (retval) {
+       /* 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;
@@ -125,7 +140,7 @@ 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);
 
@@ -437,10 +452,27 @@ static void skel_draw_down(struct usb_skel *dev)
                usb_kill_anchored_urbs(&dev->submitted);
 }
 
+static int skel_suspend(struct usb_interface *intf, pm_message_t message)
+{
+       struct usb_skel *dev = usb_get_intfdata(intf);
+
+       if (!dev)
+               return 0;
+       skel_draw_down(dev);
+       return 0;
+}
+
+static int skel_resume (struct usb_interface *intf)
+{
+       return 0;
+}
+
 static struct usb_driver skel_driver = {
        .name =         "skeleton",
        .probe =        skel_probe,
        .disconnect =   skel_disconnect,
+       .suspend =      skel_suspend,
+       .resume =       skel_resume,
        .id_table =     skel_table,
        .supports_autosuspend = 1,
 };