- for (j = vcnt; j-- ; )
- if (memcmp(page_address(pbio->bi_io_vec[j].bv_page),
- page_address(sbio->bi_io_vec[j].bv_page),
- PAGE_SIZE))
- break;
+
+ if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
+ for (j = vcnt; j-- ; ) {
+ struct page *p, *s;
+ p = pbio->bi_io_vec[j].bv_page;
+ s = sbio->bi_io_vec[j].bv_page;
+ if (memcmp(page_address(p),
+ page_address(s),
+ PAGE_SIZE))
+ break;
+ }
+ } else
+ j = 0;