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 62c68e7cee33 ("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: 62c68e7cee33 ("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>

diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c
index f33485d83d24ff9ca5c80c36bab775f26ae8e68d..0fb210e40a41272fdb20f80dc814d47bd49a8091 100644 (file)
--- a/drivers/hid/hid-hyperv.c
+++ b/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");