On Tue, 2 Jan 2018, Dan Carpenter wrote:
> On Wed, Dec 20, 2017 at 11:30:01AM +0100, Julia Lawall wrote:
> >
> >
> > On Wed, 20 Dec 2017, Dan Carpenter wrote:
> >
> > > On Tue, Dec 19, 2017 at 10:59:52PM +0200, Andy Shevchenko wrote:
> > > > @@ -914,9 +904,7 @@ static int lm3554_probe(struct i2c_client *client)
> > > > dev_err(&client->dev, "gpio request/direction_output fail");
> > > > goto fail2;
> > > > }
> > > > - if (ACPI_HANDLE(&client->dev))
> > > > - err = atomisp_register_i2c_module(&flash->sd, NULL, LED_FLASH);
> > > > - return 0;
> > > > + return atomisp_register_i2c_module(&flash->sd, NULL, LED_FLASH);
> > > > fail2:
> > > > media_entity_cleanup(&flash->sd.entity);
> > > > v4l2_ctrl_handler_free(&flash->ctrl_handler);
> > >
> > > Actually every place where we directly return a function call is wrong
> > > and needs error handling added. I've been meaning to write a Smatch
> > > check for this because it's a common anti-pattern we don't check the
> > > last function call for errors.
> > >
> > > Someone could probably do the same in Coccinelle if they want.
> >
> > I'm not sure what you are suggesting. Is every case of return f(...);
> > for any f wrong? Or is it a particular function that is of concern? Or
> > would it be that every function call that has error handling somewhere
> > should have error handling everywhere? Or is it related to what seems to
> > be the problem in the above code that err is initialized but nothing
> > happens to it?
> >
>
> I was just thinking that it's a common pattern to treat the last
> function call differently and one mistake I often see looks like this:
>
> ret = frob();
> if (ret) {
> cleanup();
> return ret;
> }
>
> return another_function();
>
> No error handling for the last function call.
OK, I see. When there was error handling code along the way, a direct
return of a function that could fail needs error handling code too.
Thanks for the clarification,
julia
