Re: [PATCH v2] tpm_crb: Remove dead code from crb_map_res()

[Stefano Garzarella]

On Sun, Oct 11, 2026 at 02:54:57AM +0300, Jarkko Sakkinen wrote:
> In all the pre-existing call sites both @iomem and @iobase_ptr are either

Do you mean @iores ?

> both NULL or have a valid address.
> 
> Add an invariant for the expeced conditions and remove a dead basic block.
> The second block is dead given that if @iomem turns out not to be NULL,
> neither can't be @iobase_ptr.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> ---
> v2:
> - Updated the commit message in order to clarify things better.
> - Updated the invariant in order to address checkpatch.pl --strict
>   errors.
>  drivers/char/tpm/tpm_crb.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index ceb4100ba400..833226966fa2 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -570,15 +570,12 @@ static void __iomem *crb_map_res(struct device *dev, struct resource *iores,
>  	if (start != new_res.start)
>  		return IOMEM_ERR_PTR(-EINVAL);
> 
> +	if (!iores != !iobase_ptr)
> +		return IOMEM_ERR_PTR(-EINVAL);
> +
>  	if (!iores)
>  		return devm_ioremap_resource(dev, &new_res);
> 
> -	if (!*iobase_ptr) {

Sorry to insist, but in the commit description we talk about @iobase_ptr 
can't be null, and I agree, but here we were checking the value of the 
pointer, so IMO this code was not dead.

But again, I know nothing on this code. So, if you think it's correct go 
head, I'm surely missing something.

Thanks,
Stefano

> -		*iobase_ptr = devm_ioremap_resource(dev, iores);
> -		if (IS_ERR(*iobase_ptr))
> -			return *iobase_ptr;
> -	}
> -
>  	return *iobase_ptr + (new_res.start - iores->start);
>  }
> 
> --
> 2.47.3
>