On Fri, Mar 22, 2019 at 03:33:37PM +0100, Arnd Bergmann wrote: > When the driver is used with a subdevice that is disabled in the > kernel configuration, clang gets a little confused about the > control flow and fails to notice that n_subdevs is only > uninitialized when subdevs is NULL, and we check for that, > leading to a false-positive warning: > > drivers/mfd/arizona-core.c:1423:19: error: variable 'n_subdevs' is > uninitialized when used here > [-Werror,-Wuninitialized] > subdevs, n_subdevs, NULL, 0, NULL); > ^~~~~~~~~ > drivers/mfd/arizona-core.c:999:15: note: initialize the variable 'n_subdevs' > to silence this warning > int n_subdevs, ret, i; > ^ > = 0 > > Ideally, we would rearrange the code to avoid all those early > initializations and have an explicit exit in each disabled case, > but it's much easier to chicken out and add one more initialization > here to shut up the warning. > > Signed-off-by: Arnd Bergmann <[email protected]>
Took me a bit to follow the flow of this function. I agree that without restructuring it, zero initializing this variable to shut up the warning is the path of least resistance (clang must evaluate variables in isolation like I did until I fully read the commit message *facepalm*). Reviewed-by: Nathan Chancellor <[email protected]> > --- > drivers/mfd/arizona-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c > index 27b61639cdc7..0ca0fc9a67fd 100644 > --- a/drivers/mfd/arizona-core.c > +++ b/drivers/mfd/arizona-core.c > @@ -996,7 +996,7 @@ int arizona_dev_init(struct arizona *arizona) > unsigned int reg, val; > int (*apply_patch)(struct arizona *) = NULL; > const struct mfd_cell *subdevs = NULL; > - int n_subdevs, ret, i; > + int n_subdevs = 0, ret, i; > > dev_set_drvdata(arizona->dev, arizona); > mutex_init(&arizona->clk_lock); > -- > 2.20.0 >
