static int check_pages_physically_contiguous(unsigned long pfn,
unsigned int offset,
size_t length)
{
unsigned long next_bfn;
int i;
int nr_pages;
next_bfn = pfn_to_bfn(pfn);
nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT;
for (i = 1; i < nr_pages; i++) {
if (pfn_to_bfn(++pfn) != ++next_bfn)
return 0;
}
return 1;
}
bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
const struct bio_vec *vec2)
{
#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(vec2->bv_page));
return __BIOVEC_PHYS_MERGEABLE(vec1, vec2) &&
((bfn1 == bfn2) || ((bfn1+1) == bfn2));
#else
/*
* XXX: Add support for merging bio_vec when using different page
* size in Xen and Linux.
*/
return 0;
#endif
}
/*
* Both of these functions should avoid PFN_PHYS because phys_addr_t
* can be 32bit when dma_addr_t is 64bit leading to a loss in
* information if the shift is done before casting to 64bit.
*/
static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
{
unsigned long bfn = pfn_to_bfn(PFN_DOWN(paddr));
dma_addr_t dma = (dma_addr_t)bfn << PAGE_SHIFT;
dma |= paddr & ~PAGE_MASK;
return dma;
}
