Re: [Xen-devel] [PATCH 02/13] xen/grant-table: Move xlated_setup_gnttab_pages to common place

[David Vrabel <david.vrabel-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org>]

On 17/11/15 09:57, shannon.zhao-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org wrote:
> From: Shannon Zhao <shannon.zhao-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> 
> Move xlated_setup_gnttab_pages to common place, so it can be reused by
> ARM to setup grant table when booting with ACPI.
[...]
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -664,6 +664,55 @@ int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
>  }
>  EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
>  
> +int __init xlated_setup_gnttab_pages(void)
> +{
> +	struct page **pages;
> +	xen_pfn_t *pfns;
> +	void *vaddr;
> +	int rc;
> +	unsigned int i;
> +	unsigned long nr_grant_frames = gnttab_max_grant_frames();
> +
> +	BUG_ON(nr_grant_frames == 0);
> +	pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL);
> +	if (!pages)
> +		return -ENOMEM;
> +
> +	pfns = kcalloc(nr_grant_frames, sizeof(pfns[0]), GFP_KERNEL);
> +	if (!pfns) {
> +		kfree(pages);
> +		return -ENOMEM;
> +	}
> +	rc = alloc_xenballooned_pages(nr_grant_frames, pages, 0 /* lowmem */);
> +	if (rc) {
> +		pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__,
> +			nr_grant_frames, rc);
> +		kfree(pages);
> +		kfree(pfns);
> +		return rc;
> +	}
> +	for (i = 0; i < nr_grant_frames; i++)
> +		pfns[i] = page_to_pfn(pages[i]);
> +
> +	vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL);
> +	if (!vaddr) {
> +		pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__,
> +			nr_grant_frames, rc);
> +		free_xenballooned_pages(nr_grant_frames, pages);
> +		kfree(pages);
> +		kfree(pfns);
> +		return -ENOMEM;
> +	}
> +	kfree(pages);

Can you move most of this function into drivers/xen/xlate_mmu.c in a
function like:

/**
 * xen_xlate_map_ballooned_pages - map a new set of ballooned pages
 * count: number of GFNs.
 * pages: returns the array of (now) ballooned pages.
 * gfns: returns the array of corresponding GFNs.
 * virt: returns the virtual address of the mapped region.
 *
 * This allocate a set of ballooned pages and maps them into the
 * kernel's address space.
 */
void *xen_xlate_map_ballooned_pages(
    unsigned int count,
    struct page **pages,
    xen_pfn_t **gfns);

David
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