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authorBenjamin Tissoires <benjamin.tissoires@gmail.com>2012-12-12 18:00:02 +0100
committerJiri Kosina <jkosina@suse.cz>2012-12-12 18:26:22 +0100
commit7a7d6d9c5fcd4b674da38e814cfc0724c67731b2 (patch)
tree8fdc9bdf269b31a706e20ac0ca1d1f135164c4c8 /drivers/hid/i2c-hid/i2c-hid.c
parent9afd09a1db93cc9084846c2b9bc0d1194743e5dc (diff)
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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: Benjamin Tissoires <benjamin.tissoires@gmail.com> Reviewed-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/hid/i2c-hid/i2c-hid.c')
-rw-r--r--drivers/hid/i2c-hid/i2c-hid.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 6e1774c3a3f..9ef222442ca 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -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)