// SPDX-License-Identifier: GPL-2.0
#include <linux/bio.h>
#include <linux/export.h>
#include <xen/xen.h>
#include <xen/page.h>

/* check if @page can be merged with 'vec1' */
bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
                               const struct page *page)
{
#if XEN_PAGE_SIZE == PAGE_SIZE
        unsigned long bfn1 = pfn_to_bfn(page_to_pfn(vec1->bv_page));
        unsigned long bfn2 = pfn_to_bfn(page_to_pfn(page));

        return bfn1 + PFN_DOWN(vec1->bv_offset + vec1->bv_len) == bfn2;
#else
        /*
         * XXX: Add support for merging bio_vec when using different page
         * size in Xen and Linux.
         */
        return false;
#endif
}