USB: g_mass_storage: thread_exits callback added

thread_exits callback has been added to fsg_common structure.
This callback is called when MSF's thread exits (is terminated
by a signal or function is unregistered).  It's then gadget's
responsibility to unregister the gadget.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 29 insertions, 14 deletions

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index a6cec37768a9..a37640eba434 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -367,6 +367,11 @@ struct fsg_common {
         struct completion       thread_notifier;
         struct task_struct      *thread_task;
 
+        /* Callback function to call when thread exits. */
+        void                    (*thread_exits)(struct fsg_common *common);
+        /* Gadget's private data. */
+        void                    *private_data;
+
         /* Vendor (8 chars), product (16 chars), release (4
          * hexadecimal digits) and NUL byte */
         char inquiry_string[8 + 16 + 4 + 1];
@@ -387,6 +392,11 @@ struct fsg_config {
         const char              *lun_name_format;
         const char              *thread_name;
 
+        /* Callback function to call when thread exits. */
+        void                    (*thread_exits)(struct fsg_common *common);
+        /* Gadget's private data. */
+        void                    *private_data;
+
         const char *vendor_name;                /*  8 characters or less */
         const char *product_name;               /* 16 characters or less */
         u16 release;
@@ -2605,11 +2615,8 @@ static int fsg_main_thread(void *common_)
         common->thread_task = NULL;
         spin_unlock_irq(&common->lock);
 
-        /* XXX */
-        /* If we are exiting because of a signal, unregister the
-         * gadget driver. */
-        /* if (test_and_clear_bit(REGISTERED, &fsg->atomic_bitflags)) */
-        /*      usb_gadget_unregister_driver(&fsg_driver); */
+        if (common->thread_exits)
+                common->thread_exits(common);
 
         /* Let the unbind and cleanup routines know the thread has exited */
         complete_and_exit(&common->thread_notifier, 0);
@@ -2672,6 +2679,8 @@ static struct fsg_common *fsg_common_init(struct fsg_common *common,
                 common->free_storage_on_release = 0;
         }
 
+        common->private_data = cfg->private_data;
+
         common->gadget = gadget;
         common->ep0 = gadget->ep0;
         common->ep0req = cdev->req;
@@ -2791,6 +2800,7 @@ static struct fsg_common *fsg_common_init(struct fsg_common *common,
 
 
         /* Tell the thread to start working */
+        common->thread_exits = cfg->thread_exits;
         common->thread_task =
                 kthread_create(fsg_main_thread, common,
                                OR(cfg->thread_name, "file-storage"));
@@ -3057,6 +3067,9 @@ fsg_config_from_params(struct fsg_config *cfg,
         cfg->product_name = 0;
         cfg->release = 0xffff;
 
+        cfg->thread_exits = 0;
+        cfg->private_data = 0;
+
         /* Finalise */
         cfg->can_stall = params->stall;
 }
diff --git a/drivers/usb/gadget/mass_storage.c b/drivers/usb/gadget/mass_storage.c
index e43ca8f4be14..19619fbf20ac 100644
--- a/drivers/usb/gadget/mass_storage.c
+++ b/drivers/usb/gadget/mass_storage.c
@@ -132,9 +132,13 @@ static struct fsg_module_parameters mod_data = {
 };
 FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
 
+static unsigned long msg_registered = 0;
+static void msg_cleanup(void);
+
 static int __init msg_do_config(struct usb_configuration *c)
 {
         struct fsg_common *common;
+        struct fsg_config config;
         int ret;
 
         if (gadget_is_otg(c->cdev->gadget)) {
@@ -142,7 +146,9 @@ static int __init msg_do_config(struct usb_configuration *c)
                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
         }
 
-        common = fsg_common_from_params(0, c->cdev, &mod_data);
+        fsg_config_from_params(&config, &mod_data);
+        config.thread_exits = (void(*)(struct fsg_common*))&msg_cleanup;
+        common = fsg_common_init(0, c->cdev, &config);
         if (IS_ERR(common))
                 return PTR_ERR(common);
 
@@ -201,11 +207,7 @@ static int __init msg_bind(struct usb_composite_dev *cdev)
                 return status;
 
         dev_info(&gadget->dev, DRIVER_DESC ", version: " DRIVER_VERSION "\n");
-        return 0;
-}
-
-static int __exit msg_unbind(struct usb_composite_dev *cdev)
-{
+        set_bit(0, &msg_registered);
         return 0;
 }
 
@@ -218,7 +220,6 @@ static struct usb_composite_driver msg_driver = {
         .dev            = &msg_device_desc,
         .strings        = dev_strings,
         .bind           = msg_bind,
-        .unbind         = __exit_p(msg_unbind),
 };
 
 MODULE_DESCRIPTION(DRIVER_DESC);
@@ -231,8 +232,9 @@ static int __init msg_init(void)
 }
 module_init(msg_init);
 
-static void __exit msg_cleanup(void)
+static void msg_cleanup(void)
 {
-        usb_composite_unregister(&msg_driver);
+        if (test_and_clear_bit(0, &msg_registered))
+                usb_composite_unregister(&msg_driver);
 }
 module_exit(msg_cleanup);