linux-kernel - [PATCH] HID: roccat: Remove use of the "exist" field

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Message-Id: <20160821133302.16265-1-s.jegen@gmail.com>
Date:   Sun, 21 Aug 2016 15:33:02 +0200
From:   Silvan Jegen <s.jegen@...il.com>
To:     Stefan Achatz <erazor_de@...rs.sourceforge.net>,
        Jiri Kosina <jikos@...nel.org>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>
Cc:     Silvan Jegen <s.jegen@...il.com>, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] HID: roccat: Remove use of the "exist" field

The "exist" field is only checked when "roccat_open" has already been
called or when we have made sure that the corresponding roccat_device is
not NULL. Since the value of the "open" field has been increased by the
"roccat_open" call, instead of checking "exist" we can just check if
"open" is equal to zero to the same effect and remove the "exist" field
as well as the code that touches it.


Signed-off-by: Silvan Jegen <s.jegen@...il.com>

---
I have tested this patch with the only Roccat hardware I own, a Roccat
Kone Pure. Testing the patch with several pieces of Roccat hardware
connected at the same time would be desirable.

 
 drivers/hid/hid-roccat.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/hid/hid-roccat.c b/drivers/hid/hid-roccat.c
index 76d06cf..7552a1e 100644
--- a/drivers/hid/hid-roccat.c
+++ b/drivers/hid/hid-roccat.c
@@ -43,7 +43,6 @@ struct roccat_device {
 	unsigned int minor;
 	int report_size;
 	int open;
-	int exist;
 	wait_queue_head_t wait;
 	struct device *dev;
 	struct hid_device *hid;
@@ -99,7 +98,7 @@ static ssize_t roccat_read(struct file *file, char __user *buffer,
 				retval = -ERESTARTSYS;
 				break;
 			}
-			if (!device->exist) {
+			if (device->open == 0) {
 				retval = -EIO;
 				break;
 			}
@@ -143,7 +142,7 @@ static unsigned int roccat_poll(struct file *file, poll_table *wait)
 	poll_wait(file, &reader->device->wait, wait);
 	if (reader->cbuf_start != reader->device->cbuf_end)
 		return POLLIN | POLLRDNORM;
-	if (!reader->device->exist)
+	if (reader->device->open == 0)
 		return POLLERR | POLLHUP;
 	return 0;
 }
@@ -224,13 +223,11 @@ static int roccat_release(struct inode *inode, struct file *file)
 	kfree(reader);
 
 	if (!--device->open) {
-		/* removing last reader */
-		if (device->exist) {
-			hid_hw_power(device->hid, PM_HINT_NORMAL);
-			hid_hw_close(device->hid);
-		} else {
-			kfree(device);
-		}
+		/* we have removed the last reader */
+		kfree(device);
+	} else {
+		hid_hw_power(device->hid, PM_HINT_NORMAL);
+		hid_hw_close(device->hid);
 	}
 
 	mutex_unlock(&devices_lock);
@@ -340,7 +337,6 @@ int roccat_connect(struct class *klass, struct hid_device *hid, int report_size)
 	mutex_init(&device->cbuf_lock);
 	device->minor = minor;
 	device->hid = hid;
-	device->exist = 1;
 	device->cbuf_end = 0;
 	device->report_size = report_size;
 
@@ -359,8 +355,6 @@ void roccat_disconnect(int minor)
 	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);
-- 
2.9.3