dm flakey: fix a bug with 32-bit highmem systems

The function page_address does not work with 32-bit systems with high
memory. Use bvec_kmap_local/kunmap_local instead.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

drivers/md/dm-flakey.c

@@ -307,8 +307,9 @@ static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
 			struct page *page = bio_iter_page(bio, iter);
 			if (unlikely(page == ZERO_PAGE(0)))
 				break;
-			segment = (page_address(page) + bio_iter_offset(bio, iter));
+			segment = bvec_kmap_local(&bvec);
 			segment[corrupt_bio_byte] = fc->corrupt_bio_value;
+			kunmap_local(segment);
 			DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
 				"(rw=%c bi_opf=%u bi_sector=%llu size=%u)\n",
 				bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,