uio: uio_hv_generic: use devm_kzalloc() for private data alloc

This is a minor cleanup for the management of the private object of this
driver. The allocation can be tied to the life-time of the hv_device
object.
This cleans up a bit the exit & error paths, since the object doesn't need
to be explicitly free'd anymore.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201119154903.82099-4-alexandru.ardelean@analog.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/uio/uio_hv_generic.c

@@ -247,14 +247,14 @@ hv_uio_probe(struct hv_device *dev,
 		return -ENOTSUPP;
 	}
 
-	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
+	pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
 		return -ENOMEM;
 
 	ret = vmbus_alloc_ring(channel, HV_RING_SIZE * PAGE_SIZE,
 			       HV_RING_SIZE * PAGE_SIZE);
 	if (ret)
-		goto fail;
+		return ret;
 
 	set_channel_read_mode(channel, HV_CALL_ISR);
 
@@ -347,8 +347,6 @@ hv_uio_probe(struct hv_device *dev,
 
 fail_close:
 	hv_uio_cleanup(dev, pdata);
-fail:
-	kfree(pdata);
 
 	return ret;
 }
@@ -364,10 +362,8 @@ hv_uio_remove(struct hv_device *dev)
 	sysfs_remove_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr);
 	uio_unregister_device(&pdata->info);
 	hv_uio_cleanup(dev, pdata);
-	hv_set_drvdata(dev, NULL);
 
 	vmbus_free_ring(dev->channel);
-	kfree(pdata);
 	return 0;
 }