From 7a7d6d9c5fcd4b674da38e814cfc0724c67731b2 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Wed, 12 Dec 2012 18:00:02 +0100 Subject: [PATCH] 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 Reviewed-by: Jean Delvare Signed-off-by: Jiri Kosina --- drivers/hid/i2c-hid/i2c-hid.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c index 6e1774c3a3f9..9ef222442ca0 100644 --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -33,6 +33,7 @@ #include #include #include +#include #include @@ -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) -- 2.20.1