[patch 2/3] Introduce BOOTMEM_EXCLUSIVE

[Vivek Goyal]

[..]
> +/*
> + * If flags is 0, then the return value is always 0 (success). If
> + * flags contains BOOTMEM_EXCLUSIVE, then -EBUSY is returned if the
> + * memory already was reserved.
> + */
> +extern int reserve_bootmem(unsigned long addr, unsigned long size, int flags);
>  #define alloc_bootmem(x) \
>  	__alloc_bootmem(x, SMP_CACHE_BYTES, __pa(MAX_DMA_ADDRESS))
>  #define alloc_bootmem_low(x) \
> --- a/mm/bootmem.c
> +++ b/mm/bootmem.c
> @@ -111,8 +111,8 @@ static unsigned long __init init_bootmem
>   * might be used for boot-time allocations - or it might get added
>   * to the free page pool later on.
>   */
> -static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
> -					unsigned long size)
> +static int __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
> +					unsigned long size, int flags)
>  {
>  	unsigned long sidx, eidx;
>  	unsigned long i;
> @@ -133,7 +133,11 @@ static void __init reserve_bootmem_core(
>  #ifdef CONFIG_DEBUG_BOOTMEM
>  			printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
>  #endif
> +			if (flags & BOOTMEM_EXCLUSIVE)
> +				return -EBUSY;

I think we should unreserve the chunks of memory we have reserved so
far (Memory reserved from sidx to i), in case of error.

Thanks
Vivek