Re: [PATCH] xen/arm: ioremap_attr: return NULL is __vmap failed

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 15/11/13 15:27, Julien Grall wrote:
> Most of ioremap_* caller check if ioremap returns NULL. Actually, if the
> physical address is non-aligned, Xen will return the pointer given by
> __vmap plus the offset in the page. So if ioremap_* fails, the caller
> will retrieve an non-NULL address and continue as if there was no error.
>
> Signed-off-by: Julien Grall <julien.grall@linaro.org>
> ---
>  xen/arch/arm/mm.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 26c6768..5137668 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -742,8 +742,13 @@ void *ioremap_attr(paddr_t pa, size_t len, unsigned int attributes)
>      unsigned long pfn = PFN_DOWN(pa);
>      unsigned int offs = pa & (PAGE_SIZE - 1);
>      unsigned int nr = PFN_UP(offs + len);
> +    void *ptr;
>  
> -    return (__vmap(&pfn, nr, 1, 1, attributes) + offs);
> +    ptr = __vmap(&pfn, nr, 1, 1, attributes);

No need to split the declaration of void *ptr and its initialisation.

~Andrew

> +    if ( ptr == NULL )
> +        return NULL;
> +
> +    return (ptr + offs);
>  }
>  
>  void *ioremap(paddr_t pa, size_t len)