usbip: usbip_host: run rebind from exit when module is removed

After removing usbip_host module, devices it releases are left without
a driver. For example, when a keyboard or a mass storage device are
bound to usbip_host when it is removed, these devices are no longer
bound to any driver.

Fix it to run device_attach() from the module exit routine to restore
the devices to their original drivers. This includes cleanup changes
and moving device_attach() code to a common routine to be called from
rebind_store() and usbip_host_exit().

Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 52 insertions, 14 deletions

diff --git a/drivers/usb/usbip/stub_dev.c b/drivers/usb/usbip/stub_dev.c
index 7813c1862941..9d0425113c4b 100644
--- a/drivers/usb/usbip/stub_dev.c
+++ b/drivers/usb/usbip/stub_dev.c
@@ -448,12 +448,8 @@ static void stub_disconnect(struct usb_device *udev)
         busid_priv->sdev = NULL;
         stub_device_free(sdev);
 
-        if (busid_priv->status == STUB_BUSID_ALLOC) {
+        if (busid_priv->status == STUB_BUSID_ALLOC)
                 busid_priv->status = STUB_BUSID_ADDED;
-        } else {
-                busid_priv->status = STUB_BUSID_OTHER;
-                del_match_busid((char *)udev_busid);
-        }
 }
 
 #ifdef CONFIG_PM
diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c
index fb46bd62d538..587b9bc10042 100644
--- a/drivers/usb/usbip/stub_main.c
+++ b/drivers/usb/usbip/stub_main.c
@@ -14,6 +14,7 @@
 #define DRIVER_DESC "USB/IP Host Driver"
 
 struct kmem_cache *stub_priv_cache;
+
 /*
  * busid_tables defines matching busids that usbip can grab. A user can change
  * dynamically what device is locally used and what device is exported to a
@@ -169,6 +170,51 @@ static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
 }
 static DRIVER_ATTR_RW(match_busid);
 
+static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
+{
+        int ret;
+
+        /* device_attach() callers should hold parent lock for USB */
+        if (busid_priv->udev->dev.parent)
+                device_lock(busid_priv->udev->dev.parent);
+        ret = device_attach(&busid_priv->udev->dev);
+        if (busid_priv->udev->dev.parent)
+                device_unlock(busid_priv->udev->dev.parent);
+        if (ret < 0) {
+                dev_err(&busid_priv->udev->dev, "rebind failed\n");
+                return ret;
+        }
+        return 0;
+}
+
+static void stub_device_rebind(void)
+{
+#if IS_MODULE(CONFIG_USBIP_HOST)
+        struct bus_id_priv *busid_priv;
+        int i;
+
+        /* update status to STUB_BUSID_OTHER so probe ignores the device */
+        spin_lock(&busid_table_lock);
+        for (i = 0; i < MAX_BUSID; i++) {
+                if (busid_table[i].name[0] &&
+                    busid_table[i].shutdown_busid) {
+                        busid_priv = &(busid_table[i]);
+                        busid_priv->status = STUB_BUSID_OTHER;
+                }
+        }
+        spin_unlock(&busid_table_lock);
+
+        /* now run rebind */
+        for (i = 0; i < MAX_BUSID; i++) {
+                if (busid_table[i].name[0] &&
+                    busid_table[i].shutdown_busid) {
+                        busid_priv = &(busid_table[i]);
+                        do_rebind(busid_table[i].name, busid_priv);
+                }
+        }
+#endif
+}
+
 static ssize_t rebind_store(struct device_driver *dev, const char *buf,
                                  size_t count)
 {
@@ -189,16 +235,9 @@ static ssize_t rebind_store(struct device_driver *dev, const char *buf,
         /* mark the device for deletion so probe ignores it during rescan */
         bid->status = STUB_BUSID_OTHER;
 
-        /* device_attach() callers should hold parent lock for USB */
-        if (bid->udev->dev.parent)
-                device_lock(bid->udev->dev.parent);
-        ret = device_attach(&bid->udev->dev);
-        if (bid->udev->dev.parent)
-                device_unlock(bid->udev->dev.parent);
-        if (ret < 0) {
-                dev_err(&bid->udev->dev, "rebind failed\n");
+        ret = do_rebind((char *) buf, bid);
+        if (ret < 0)
                 return ret;
-        }
 
         /* delete device from busid_table */
         del_match_busid((char *) buf);
@@ -323,6 +362,9 @@ static void __exit usbip_host_exit(void)
          */
         usb_deregister_device_driver(&stub_driver);
 
+        /* initiate scan to attach devices */
+        stub_device_rebind();
+
         kmem_cache_destroy(stub_priv_cache);
 }