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Commit 7a7d6d9c authored by Benjamin Tissoires's avatar Benjamin Tissoires Committed by Jiri Kosina
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HID: i2c-hid: add mutex protecting open/close race 



We should not enter close function while someone else is in open.
This mutex prevents this race.

There is also no need to override the ret value with -EIO in case of
a failure of i2c_hid_set_power.

Signed-off-by: default avatarBenjamin Tissoires <benjamin.tissoires@gmail.com>
Reviewed-by: default avatarJean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 9afd09a1

drivers/hid/i2c-hid/i2c-hid.c

+11 −3
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#include <linux/jiffies.h>

#include <linux/kernel.h>

#include <linux/hid.h>

#include <linux/mutex.h>



#include <linux/i2c/i2c-hid.h>
@@ -117,6 +118,8 @@ static const struct i2c_hid_cmd hid_set_power_cmd = { I2C_HID_CMD(0x08) }; 
 * static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };

 */



static DEFINE_MUTEX(i2c_hid_open_mut);



/* The main device structure */

struct i2c_hid {

	struct i2c_client	*client;	/* i2c client */
@@ -641,17 +644,20 @@ static int i2c_hid_open(struct hid_device *hid) 
{

	struct i2c_client *client = hid->driver_data;

	struct i2c_hid *ihid = i2c_get_clientdata(client);

	int ret;

	int ret = 0;



	mutex_lock(&i2c_hid_open_mut);

	if (!hid->open++) {

		ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);

		if (ret) {

			hid->open--;

			return -EIO;

			goto done;

		}

		set_bit(I2C_HID_STARTED, &ihid->flags);

	}

	return 0;

done:

	mutex_unlock(&i2c_hid_open_mut);

	return ret;

}



static void i2c_hid_close(struct hid_device *hid)
@@ -663,12 +669,14 @@ static void i2c_hid_close(struct hid_device *hid) 
	 * data acquistion due to a resumption we no longer

	 * care about

	 */

	mutex_lock(&i2c_hid_open_mut);

	if (!--hid->open) {

		clear_bit(I2C_HID_STARTED, &ihid->flags);



		/* Save some power */

		i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);

	}

	mutex_unlock(&i2c_hid_open_mut);

}



static int i2c_hid_power(struct hid_device *hid, int lvl)