Re: [PATCH] tvp7002: use devm_kzalloc() instead of kzalloc()

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Thursday 03 January 2013 14:31:20 Laurent Pinchart wrote:
> On Thursday 03 January 2013 18:52:42 Lad, Prabhakar wrote:
> > I2C drivers can use devm_kzalloc() too in their .probe() methods. Doing so
> > simplifies their clean up paths.
> > 
> > Signed-off-by: Lad, Prabhakar <prabhakar.lad@ti.com>
> > Signed-off-by: Manjunath Hadli <manjunath.hadli@ti.com>
> > ---
> > 
> >  drivers/media/i2c/tvp7002.c |   10 ++--------
> >  1 files changed, 2 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/tvp7002.c b/drivers/media/i2c/tvp7002.c
> > index fb6a5b5..2d4c86e 100644
> > --- a/drivers/media/i2c/tvp7002.c
> > +++ b/drivers/media/i2c/tvp7002.c
> > @@ -1036,7 +1036,7 @@ static int tvp7002_probe(struct i2c_client *c, const
> > struct i2c_device_id *id) return -ENODEV;
> > 
> >  	}
> > 
> > -	device = kzalloc(sizeof(struct tvp7002), GFP_KERNEL);
> > +	device = devm_kzalloc(&c->dev, sizeof(struct tvp7002), GFP_KERNEL);
> > 
> >  	if (!device)
> >  	
> >  		return -ENOMEM;
> > 
> > @@ -1088,17 +1088,12 @@ static int tvp7002_probe(struct i2c_client *c,
> > const struct i2c_device_id *id) V4L2_CID_GAIN, 0, 255, 1, 0);
> > 
> >  	sd->ctrl_handler = &device->hdl;
> >  	if (device->hdl.error) {
> > 
> > -		int err = device->hdl.error;
> > -
> > 
> >  		v4l2_ctrl_handler_free(&device->hdl);
> > 
> > -		kfree(device);
> > -		return err;
> > +		return device->hdl.error;
> 
> At this point device->hdl as been freed (or rather uninitialized, as the
> structure is not dynamically allocated by the control framework), so device-
> >hdl.error is undefined. That's why you need the local err variable.

And this comment holds true for the other patches in this series.

> >
> >  	}
> >  	v4l2_ctrl_handler_setup(&device->hdl);
> >  
> >  found_error:
> > -	if (error < 0)
> > -		kfree(device);
> 
> You can remove the found_error label and return errors directly instead of
> using goto's.
> 
> >  	return error;
> 
> And this can then be turned into return 0.
> 
> >  }
> > 
> > @@ -1120,7 +1115,6 @@ static int tvp7002_remove(struct i2c_client *c)
> > 
> >  	v4l2_device_unregister_subdev(sd);
> >  	v4l2_ctrl_handler_free(&device->hdl);
> > 
> > -	kfree(device);
> > 
> >  	return 0;
> >  
> >  }

-- 
Regards,

Laurent Pinchart