| Message ID | 1475073244-23068-2-git-send-email-benjamin.tissoires@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Wed, Sep 28, 2016 at 04:34:01PM +0200, Benjamin Tissoires wrote: > i2c_smbus_read_block_data() returns negative errno else the number of > data bytes in the slave's response. > > Checking for error not null means the function always fails if the device > answers properly. > > So given that we read 3 bytes and access those, better check that we > actually read those 3 bytes. > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> > --- > drivers/input/mouse/elan_i2c_smbus.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/input/mouse/elan_i2c_smbus.c b/drivers/input/mouse/elan_i2c_smbus.c > index cb6aecb..9b43b55 100644 > --- a/drivers/input/mouse/elan_i2c_smbus.c > +++ b/drivers/input/mouse/elan_i2c_smbus.c > @@ -226,7 +226,7 @@ static int elan_smbus_get_max(struct i2c_client *client, > u8 val[3]; > > error = i2c_smbus_read_block_data(client, ETP_SMBUS_RANGE_CMD, val); > - if (error) { > + if (error != 3) { > dev_err(&client->dev, "failed to get dimensions: %d\n", error); > return error; Unfortunately that means you'll report success if you get 0 from i2c_smbus_read_block_data() or confuse upper layers with positive errors. I'll change this to: ret = i2c_smbus_read_block_data(); if (ret != 3) { error = ret < 0 ? ret : -EIO; ... } Thanks. > } > @@ -245,7 +245,7 @@ static int elan_smbus_get_resolution(struct i2c_client *client, > > error = i2c_smbus_read_block_data(client, > ETP_SMBUS_RESOLUTION_CMD, val); > - if (error) { > + if (error != 3) { > dev_err(&client->dev, "failed to get resolution: %d\n", error); > return error; > } > @@ -265,7 +265,7 @@ static int elan_smbus_get_num_traces(struct i2c_client *client, > > error = i2c_smbus_read_block_data(client, > ETP_SMBUS_XY_TRACENUM_CMD, val); > - if (error) { > + if (error != 3) { > dev_err(&client->dev, "failed to get trace info: %d\n", error); > return error; > } > -- > 2.7.4 >
diff --git a/drivers/input/mouse/elan_i2c_smbus.c b/drivers/input/mouse/elan_i2c_smbus.c index cb6aecb..9b43b55 100644 --- a/drivers/input/mouse/elan_i2c_smbus.c +++ b/drivers/input/mouse/elan_i2c_smbus.c @@ -226,7 +226,7 @@ static int elan_smbus_get_max(struct i2c_client *client, u8 val[3]; error = i2c_smbus_read_block_data(client, ETP_SMBUS_RANGE_CMD, val); - if (error) { + if (error != 3) { dev_err(&client->dev, "failed to get dimensions: %d\n", error); return error; } @@ -245,7 +245,7 @@ static int elan_smbus_get_resolution(struct i2c_client *client, error = i2c_smbus_read_block_data(client, ETP_SMBUS_RESOLUTION_CMD, val); - if (error) { + if (error != 3) { dev_err(&client->dev, "failed to get resolution: %d\n", error); return error; } @@ -265,7 +265,7 @@ static int elan_smbus_get_num_traces(struct i2c_client *client, error = i2c_smbus_read_block_data(client, ETP_SMBUS_XY_TRACENUM_CMD, val); - if (error) { + if (error != 3) { dev_err(&client->dev, "failed to get trace info: %d\n", error); return error; }
i2c_smbus_read_block_data() returns negative errno else the number of data bytes in the slave's response. Checking for error not null means the function always fails if the device answers properly. So given that we read 3 bytes and access those, better check that we actually read those 3 bytes. Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> --- drivers/input/mouse/elan_i2c_smbus.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)