Re: [Xen-devel] [PATCH V4 4/8] xen/common: Introduce _xrealloc function

[Jan Beulich <jbeulich@xxxxxxxx>]

On 23.09.2019 14:50, Oleksandr wrote:
> Does the diff below is close to what you meant?

Almost.

> @@ -598,10 +621,70 @@ void *_xzalloc(unsigned long size, unsigned long align)
>       return p ? memset(p, 0, size) : p;
>   }
> 
> -void xfree(void *p)
> +void *_xrealloc(void *ptr, unsigned long size, unsigned long align)
>   {
> -    struct bhdr *b;
> +    unsigned long curr_size, tmp_size;
> +    void *p;
> +
> +    if ( !size )
> +    {
> +        xfree(ptr);
> +        return ZERO_BLOCK_PTR;
> +    }
> +
> +    if ( ptr == NULL || ptr == ZERO_BLOCK_PTR )
> +        return _xmalloc(size, align);
> +
> +    ASSERT((align & (align - 1)) == 0);
> +    if ( align < MEM_ALIGN )
> +        align = MEM_ALIGN;
> +
> +    tmp_size = size + align - MEM_ALIGN;
> +
> +    if ( tmp_size < PAGE_SIZE )
> +        tmp_size = (tmp_size < MIN_BLOCK_SIZE) ? MIN_BLOCK_SIZE :
> +            ROUNDUP_SIZE(tmp_size);
> +
> +    if ( !((unsigned long)ptr & (PAGE_SIZE - 1)) )
> +    {
> +        curr_size = (unsigned long)PFN_ORDER(virt_to_page(ptr)) << 
> PAGE_SHIFT;
> +
> +        if ( tmp_size <= curr_size && ((unsigned long)ptr & (align - 1)) == 
> 0 )

You mean "size" here I think, not "tmp_size". See how xmalloc_whole_pages()
gets called from _xmalloc() with an "adjusted back" value.

And as said, please clean up the code you move or add anew: Use casts
only where really needed, transform types to appropriate "modern" ones,
etc.

Jan

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