[lvc-project] [PATCH 1/2] HID: roccat: fix locking in roccat_connect() and roccat_disconnect()

[Dmitry Antipov]

Extend critical section in roccat_connect() to ensure that partially
initialized 'struct roccat_device' is never exposed in 'devices' list,
and do the same in roccat_disconnect() to avoid racy 'devices' access
against roccat_release().

Signed-off-by: Dmitry Antipov <dmantipov at yandex.ru>
---
 drivers/hid/hid-roccat.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/hid/hid-roccat.c b/drivers/hid/hid-roccat.c
index 4f15eb951039..5deb6da8d4f7 100644
--- a/drivers/hid/hid-roccat.c
+++ b/drivers/hid/hid-roccat.c
@@ -344,8 +344,6 @@ int roccat_connect(const struct class *klass, struct hid_device *hid, int report
 		return temp;
 	}
 
-	mutex_unlock(&devices_lock);
-
 	init_waitqueue_head(&device->wait);
 	INIT_LIST_HEAD(&device->readers);
 	mutex_init(&device->readers_lock);
@@ -356,6 +354,7 @@ int roccat_connect(const struct class *klass, struct hid_device *hid, int report
 	device->cbuf_end = 0;
 	device->report_size = report_size;
 
+	mutex_unlock(&devices_lock);
 	return minor;
 }
 EXPORT_SYMBOL_GPL(roccat_connect);
@@ -369,15 +368,12 @@ void roccat_disconnect(int minor)
 
 	mutex_lock(&devices_lock);
 	device = devices[minor];
-	mutex_unlock(&devices_lock);
 
 	device->exist = 0; /* TODO exist maybe not needed */
 
 	device_destroy(device->dev->class, MKDEV(roccat_major, minor));
 
-	mutex_lock(&devices_lock);
 	devices[minor] = NULL;
-	mutex_unlock(&devices_lock);
 
 	if (device->open) {
 		hid_hw_close(device->hid);
@@ -385,6 +381,8 @@ void roccat_disconnect(int minor)
 	} else {
 		roccat_free_device(device);
 	}
+
+	mutex_unlock(&devices_lock);
 }
 EXPORT_SYMBOL_GPL(roccat_disconnect);
 
-- 
2.55.0