HID: hyperv: streamline driver probe to avoid devres issues

JIRA: https://issues.redhat.com/browse/RHEL-67329

commit 66ef47f
Author: Vitaly Kuznetsov <vkuznets@redhat.com>
Date:   Mon Nov 11 14:12:40 2024 +0100

    HID: hyperv: streamline driver probe to avoid devres issues

    It was found that unloading 'hid_hyperv' module results in a devres
    complaint:

     ...
     hv_vmbus: unregistering driver hid_hyperv
     ------------[ cut here ]------------
     WARNING: CPU: 2 PID: 3983 at drivers/base/devres.c:691 devres_release_group+0x1f2/0x2c0
     ...
     Call Trace:
      <TASK>
      ? devres_release_group+0x1f2/0x2c0
      ? __warn+0xd1/0x1c0
      ? devres_release_group+0x1f2/0x2c0
      ? report_bug+0x32a/0x3c0
      ? handle_bug+0x53/0xa0
      ? exc_invalid_op+0x18/0x50
      ? asm_exc_invalid_op+0x1a/0x20
      ? devres_release_group+0x1f2/0x2c0
      ? devres_release_group+0x90/0x2c0
      ? rcu_is_watching+0x15/0xb0
      ? __pfx_devres_release_group+0x10/0x10
      hid_device_remove+0xf5/0x220
      device_release_driver_internal+0x371/0x540
      ? klist_put+0xf3/0x170
      bus_remove_device+0x1f1/0x3f0
      device_del+0x33f/0x8c0
      ? __pfx_device_del+0x10/0x10
      ? cleanup_srcu_struct+0x337/0x500
      hid_destroy_device+0xc8/0x130
      mousevsc_remove+0xd2/0x1d0 [hid_hyperv]
      device_release_driver_internal+0x371/0x540
      driver_detach+0xc5/0x180
      bus_remove_driver+0x11e/0x2a0
      ? __mutex_unlock_slowpath+0x160/0x5e0
      vmbus_driver_unregister+0x62/0x2b0 [hv_vmbus]
      ...

    And the issue seems to be that the corresponding devres group is not
    allocated. Normally, devres_open_group() is called from
    __hid_device_probe() but Hyper-V HID driver overrides 'hid_dev->driver'
    with 'mousevsc_hid_driver' stub and basically re-implements
    __hid_device_probe() by calling hid_parse() and hid_hw_start() but not
    devres_open_group(). hid_device_probe() does not call __hid_device_probe()
    for it. Later, when the driver is removed, hid_device_remove() calls
    devres_release_group() as it doesn't check whether hdev->driver was
    initially overridden or not.

    The issue seems to be related to the commit 62c68e7 ("HID: ensure
    timely release of driver-allocated resources") but the commit itself seems
    to be correct.

    Fix the issue by dropping the 'hid_dev->driver' override and using
    hid_register_driver()/hid_unregister_driver() instead. Alternatively, it
    would have been possible to rely on the default handling but
    HID_CONNECT_DEFAULT implies HID_CONNECT_HIDRAW and it doesn't seem to work
    for mousevsc as-is.

    Fixes: 62c68e7 ("HID: ensure timely release of driver-allocated resources")
    Suggested-by: Michael Kelley <mhklinux@outlook.com>
    Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
    Reviewed-by: Michael Kelley <mhklinux@outlook.com>
    Tested-by: Saurabh Sengar <ssengar@linux.microsoft.com>
    Signed-off-by: Jiri Kosina <jkosina@suse.com>

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>

Author: vittyvk

drivers/hid/hid-hyperv.c

@@ -422,6 +422,25 @@ static int mousevsc_hid_raw_request(struct hid_device *hid,
 	return 0;
 }
 
+static int mousevsc_hid_probe(struct hid_device *hid_dev, const struct hid_device_id *id)
+{
+	int ret;
+
+	ret = hid_parse(hid_dev);
+	if (ret) {
+		hid_err(hid_dev, "parse failed\n");
+		return ret;
+	}
+
+	ret = hid_hw_start(hid_dev, HID_CONNECT_HIDINPUT | HID_CONNECT_HIDDEV);
+	if (ret) {
+		hid_err(hid_dev, "hw start failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
 static const struct hid_ll_driver mousevsc_ll_driver = {
 	.parse = mousevsc_hid_parse,
 	.open = mousevsc_hid_open,
@@ -431,7 +450,16 @@ static const struct hid_ll_driver mousevsc_ll_driver = {
 	.raw_request = mousevsc_hid_raw_request,
 };
 
-static struct hid_driver mousevsc_hid_driver;
+static const struct hid_device_id mousevsc_devices[] = {
+	{ HID_DEVICE(BUS_VIRTUAL, HID_GROUP_ANY, 0x045E, 0x0621) },
+	{ }
+};
+
+static struct hid_driver mousevsc_hid_driver = {
+	.name = "hid-hyperv",
+	.id_table = mousevsc_devices,
+	.probe = mousevsc_hid_probe,
+};
 
 static int mousevsc_probe(struct hv_device *device,
 			const struct hv_vmbus_device_id *dev_id)
@@ -473,7 +501,6 @@ static int mousevsc_probe(struct hv_device *device,
 	}
 
 	hid_dev->ll_driver = &mousevsc_ll_driver;
-	hid_dev->driver = &mousevsc_hid_driver;
 	hid_dev->bus = BUS_VIRTUAL;
 	hid_dev->vendor = input_dev->hid_dev_info.vendor;
 	hid_dev->product = input_dev->hid_dev_info.product;
@@ -488,20 +515,6 @@ static int mousevsc_probe(struct hv_device *device,
 	if (ret)
 		goto probe_err2;
 
-
-	ret = hid_parse(hid_dev);
-	if (ret) {
-		hid_err(hid_dev, "parse failed\n");
-		goto probe_err2;
-	}
-
-	ret = hid_hw_start(hid_dev, HID_CONNECT_HIDINPUT | HID_CONNECT_HIDDEV);
-
-	if (ret) {
-		hid_err(hid_dev, "hw start failed\n");
-		goto probe_err2;
-	}
-
 	device_init_wakeup(&device->device, true);
 
 	input_dev->connected = true;
@@ -579,12 +592,23 @@ static struct  hv_driver mousevsc_drv = {
 
 static int __init mousevsc_init(void)
 {
-	return vmbus_driver_register(&mousevsc_drv);
+	int ret;
+
+	ret = hid_register_driver(&mousevsc_hid_driver);
+	if (ret)
+		return ret;
+
+	ret = vmbus_driver_register(&mousevsc_drv);
+	if (ret)
+		hid_unregister_driver(&mousevsc_hid_driver);
+
+	return ret;
 }
 
 static void __exit mousevsc_exit(void)
 {
 	vmbus_driver_unregister(&mousevsc_drv);
+	hid_unregister_driver(&mousevsc_hid_driver);
 }
 
 MODULE_LICENSE("GPL");