crypto: nx - fix physical addresses added to sg lists

The co-processor receives data to be hashed through scatter/gather lists
pointing to physical addresses. When a vmalloc'ed data is given, the
driver must calculate the physical address to each page of the data.

However the current version of it just calculates the physical address
once and keeps incrementing it even when a page boundary is crossed.
This patch fixes this behaviour.
Reviewed-by: Fionnuala Gunter <fin@linux.vnet.ibm.com>
Reviewed-by: Joel Schopp <jschopp@linux.vnet.ibm.com>
Reviewed-by: Joy Latten <jmlatten@linux.vnet.ibm.com>
Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/nx/nx.c

@@ -114,13 +114,29 @@ struct nx_sg *nx_build_sg_list(struct nx_sg *sg_head,
 	 * have been described (or @sgmax elements have been written), the
 	 * loop ends. min_t is used to ensure @end_addr falls on the same page
 	 * as sg_addr, if not, we need to create another nx_sg element for the
-	 * data on the next page */
+	 * data on the next page.
+	 *
+	 * Also when using vmalloc'ed data, every time that a system page
+	 * boundary is crossed the physical address needs to be re-calculated.
+	 */
 	for (sg = sg_head; sg_len < len; sg++) {
+		u64 next_page;
+
 		sg->addr = sg_addr;
-		sg_addr = min_t(u64, NX_PAGE_NUM(sg_addr + NX_PAGE_SIZE), end_addr);
-		sg->len = sg_addr - sg->addr;
+		sg_addr = min_t(u64, NX_PAGE_NUM(sg_addr + NX_PAGE_SIZE),
+				end_addr);
+
+		next_page = (sg->addr & PAGE_MASK) + PAGE_SIZE;
+		sg->len = min_t(u64, sg_addr, next_page) - sg->addr;
 		sg_len += sg->len;
 
+		if (sg_addr >= next_page &&
+				is_vmalloc_addr(start_addr + sg_len)) {
+			sg_addr = page_to_phys(vmalloc_to_page(
+						start_addr + sg_len));
+			end_addr = sg_addr + len - sg_len;
+		}
+
 		if ((sg - sg_head) == sgmax) {
 			pr_err("nx: scatter/gather list overflow, pid: %d\n",
 			       current->pid);