drivers/xen/biomerge.c

   1 #include <linux/bio.h>
   2 #include <linux/io.h>
   3 #include <linux/export.h>
   4 #include <xen/page.h>
   5
   6 bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
   7                                const struct bio_vec *vec2)
   8 {
   9 #if XEN_PAGE_SIZE == PAGE_SIZE
  10         unsigned long bfn1 = pfn_to_bfn(page_to_pfn(vec1->bv_page));
  11         unsigned long bfn2 = pfn_to_bfn(page_to_pfn(vec2->bv_page));
  12
  13         return __BIOVEC_PHYS_MERGEABLE(vec1, vec2) &&
  14                 ((bfn1 == bfn2) || ((bfn1+1) == bfn2));
  15 #else
  16         /*
  17          * XXX: Add support for merging bio_vec when using different page
  18          * size in Xen and Linux.
  19          */
  20         return 0;
  21 #endif
  22 }
  23 EXPORT_SYMBOL(xen_biovec_phys_mergeable);