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@xxxxxxxxx>
---
Hi Jiri, hi Jean,
this is the last patch that came from the last review. Sorry I took so long to
do it, but I thought it would have raised other problems. In the end, the
changes are pretty straightforward, and it would be great to have this one
in 3.8-rc0 too.
Anyway, Jiri, the choice is yours.
Cheers,
Benjamin
drivers/hid/i2c-hid/i2c-hid.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 6e1774c..74dfc33 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -117,6 +117,8 @@ 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 +643,20 @@ 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 +668,14 @@ 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)
--
1.8.0.2
--
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