Re: [Minios-devel] [UNIKRAFT PATCH v2] lib/ukalloc: fix wrong return value in uk_malloc_ifpages

[Costin Lupu <costin.lup@xxxxxxxxx>]

Hi Florian,

Just a minor thing, please see inline.

On 08/30/2018 05:08 PM, Florian Schmidt wrote:
> uk_malloc_ifpages returned the wrong pointer, because it added
> sizeof(size_t) to a pointer of type size_t. Hence, the return value
> wasn't offset from intptr by size_t bytes, but by size_t*size_t bytes.
> 
> This patch makes intptr a uintptr_t in places in which its property as
> size_t* isn't used.
> 
> Signed-off-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>
> ---
>  lib/ukalloc/alloc.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/lib/ukalloc/alloc.c b/lib/ukalloc/alloc.c
> index 52e9a77..fb38bcb 100644
> --- a/lib/ukalloc/alloc.c
> +++ b/lib/ukalloc/alloc.c
> @@ -167,7 +167,7 @@ static inline size_t uk_alloc_size_to_order(size_t size)
>  
>  void *uk_malloc_ifpages(struct uk_alloc *a, size_t size)
>  {
> -     size_t *intptr;
> +     uintptr_t intptr;
>       size_t order;
>       size_t realsize = sizeof(order) + size;
>  
> @@ -176,13 +176,13 @@ void *uk_malloc_ifpages(struct uk_alloc *a, size_t size)
>               return NULL;
>  
>       order = uk_alloc_size_to_order(realsize);
> -     intptr = uk_palloc(a, order);
> +     intptr = (uintptr_t)uk_palloc(a, order);
>  
>       if (!intptr)
>               return NULL;
>  
> -     *intptr = order;
> -     return intptr + sizeof(order);
> +     *(size_t *)intptr = order;
> +     return (void *)(intptr + sizeof(order));
>  }
>  
>  void uk_free_ifpages(struct uk_alloc *a, void *ptr)
> @@ -229,7 +229,7 @@ void *uk_realloc_ifpages(struct uk_alloc *a, void *ptr, 
> size_t size)
>  int uk_posix_memalign_ifpages(struct uk_alloc *a,
>                               void **memptr, size_t align, size_t size)
>  {
> -     size_t *intptr;
> +     uintptr_t *intptr;

I guess intptr should be of type uintptr_t (and not uintptr_t *).

>       size_t realsize;
>       size_t order;
>  
> @@ -259,7 +259,7 @@ int uk_posix_memalign_ifpages(struct uk_alloc *a,
>       if (!intptr)
>               return ENOMEM;
>  
> -     *intptr = order;
> +     *(size_t *)intptr = order;
>       *memptr = (void *) ALIGN_UP((uintptr_t)intptr + sizeof(order), align);

And here you would get rid of the cast to uintptr_t.

>       return 0;
>  }
> 


Cheers,
Costin

_______________________________________________
Minios-devel mailing list
Minios-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/minios-devel