[lvc-project] [PATCH v2 3/4] HID: roccat: examine readers to check whether the device is opened

[Dmitry Antipov]

Use list_empty() to check whether the device has active readers,
thus dropping explicit 'open' flag from 'struct roccat_device'.

Signed-off-by: Dmitry Antipov <dmantipov at yandex.ru>
---
v2: initial version to join the series
---
 drivers/hid/hid-roccat.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/hid/hid-roccat.c b/drivers/hid/hid-roccat.c
index 007778922c21..d1df4ec34a1e 100644
--- a/drivers/hid/hid-roccat.c
+++ b/drivers/hid/hid-roccat.c
@@ -39,7 +39,6 @@ struct roccat_report {
 struct roccat_device {
 	unsigned int minor;
 	int report_size;
-	int open;
 	int exist;
 	wait_queue_head_t wait;
 	struct device *dev;
@@ -177,18 +176,15 @@ static int roccat_open(struct inode *inode, struct file *file)
 
 	mutex_lock(&device->readers_lock);
 
-	if (!device->open++) {
+	if (list_empty(&device->readers)) {
 		/* power on device on adding first reader */
 		error = hid_hw_power(device->hid, PM_HINT_FULLON);
-		if (error < 0) {
-			--device->open;
+		if (error < 0)
 			goto exit_err_readers;
-		}
 
 		error = hid_hw_open(device->hid);
 		if (error < 0) {
 			hid_hw_power(device->hid, PM_HINT_NORMAL);
-			--device->open;
 			goto exit_err_readers;
 		}
 	}
@@ -213,18 +209,20 @@ static int roccat_release(struct inode *inode, struct file *file)
 {
 	struct roccat_reader *reader = file->private_data;
 	struct roccat_device *device = reader->device;
+	bool open;
 
 	if (WARN_ON_ONCE(!device))
 		return -ENODEV;
 
 	mutex_lock(&device->readers_lock);
 	list_del(&reader->node);
+	open = !list_empty(&device->readers);
 	mutex_unlock(&device->readers_lock);
 	kfree(reader);
 
 	mutex_lock(&devices_lock);
 
-	if (!--device->open) {
+	if (!open) {
 		/* removing last reader */
 		if (device->exist) {
 			hid_hw_power(device->hid, PM_HINT_NORMAL);
@@ -360,6 +358,7 @@ EXPORT_SYMBOL_GPL(roccat_connect);
 void roccat_disconnect(int minor)
 {
 	struct roccat_device *device;
+	bool open;
 
 	mutex_lock(&devices_lock);
 	device = devices[minor];
@@ -370,7 +369,11 @@ void roccat_disconnect(int minor)
 
 	devices[minor] = NULL;
 
-	if (device->open) {
+	mutex_lock(&device->readers_lock);
+	open = !list_empty(&device->readers);
+	mutex_unlock(&device->readers_lock);
+
+	if (open) {
 		hid_hw_close(device->hid);
 		wake_up_interruptible(&device->wait);
 	} else {
-- 
2.55.0