input: synaptics_dsx: reallocate buffer under lock.

Prevent concurrent usage & re-allocation of the wr_buf variable.
Based off patch by chengengjia <chengjia4574@gmail.com>.

BUG: 33001936
Change-Id: I88d78e1ec0fc9e88b1e6824c06161b67d01136ec
Signed-off-by: Andrew Chant <achant@google.com>
Git-commit: d740e7228bd1578ed01762998b2a86e7df56e608
Git-repo: https://android.googlesource.com/kernel/msm
Signed-off-by: Dennis Cagle <d-cagle@codeaurora.org>

diff --git a/drivers/input/touchscreen/synaptics_dsx_2.6/synaptics_dsx_i2c.c b/drivers/input/touchscreen/synaptics_dsx_2.6/synaptics_dsx_i2c.c
index f936f3c..563ce16 100644 (file)
--- a/drivers/input/touchscreen/synaptics_dsx_2.6/synaptics_dsx_i2c.c
+++ b/drivers/input/touchscreen/synaptics_dsx_2.6/synaptics_dsx_i2c.c
@@ -445,11 +445,11 @@ static int synaptics_rmi4_i2c_write(struct synaptics_rmi4_data *rmi4_data,
        struct i2c_client *i2c = to_i2c_client(rmi4_data->pdev->dev.parent);
        struct i2c_msg msg[1];
 
+       mutex_lock(&rmi4_data->rmi4_io_ctrl_mutex);
+
        retval = synaptics_rmi4_i2c_alloc_buf(rmi4_data, length + 1);
        if (retval < 0)
-               return retval;
-
-       mutex_lock(&rmi4_data->rmi4_io_ctrl_mutex);
+               goto exit;
 
        retval = synaptics_rmi4_i2c_set_page(rmi4_data, addr);
        if (retval != PAGE_SELECT_LEN) {