page-server: Tune up the encode/decode helpers

Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/page-xfer.c

@@ -48,11 +48,11 @@ static void psi2iovec(struct page_server_iov *ps, struct iovec *iov)
 #define PS_TYPE_PID	(1)
 #define PS_TYPE_SHMEM	(2)
 /*
- * XXX: When adding new types here check decode_pm_type for legacy
+ * XXX: When adding new types here check decode_pm for legacy
  * numbers that can be met from older CRIUs
  */
 
-static inline u64 encode_pm_id(int type, long id)
+static inline u64 encode_pm(int type, long id)
 {
 	if (type == CR_FD_PAGEMAP)
 		type = PS_TYPE_PID;
@@ -66,7 +66,7 @@ static inline u64 encode_pm_id(int type, long id)
 	return ((u64)id) << PS_TYPE_BITS | type;
 }
 
-static int decode_pm_type(u64 dst_id)
+static int decode_pm(u64 dst_id, long *id)
 {
 	int type;
 
@@ -83,6 +83,7 @@ static int decode_pm_type(u64 dst_id)
 	case 16: /* 1.2 */
 	case 17: /* 1.0 1.1 */
 	case PS_TYPE_PID:
+		*id = dst_id >> PS_TYPE_BITS;
 		type = CR_FD_PAGEMAP;
 		break;
 	case 27: /* 1.3 */
@@ -92,6 +93,7 @@ static int decode_pm_type(u64 dst_id)
 	case 33: /* 1.0 1.1 3.1 3.2 */
 	case 34: /* 2.* 3.0 */
 	case PS_TYPE_SHMEM:
+		*id = dst_id >> PS_TYPE_BITS;
 		type = CR_FD_SHMEM_PAGEMAP;
 		break;
 	default:
@@ -102,11 +104,6 @@ static int decode_pm_type(u64 dst_id)
 	return type;
 }
 
-static long decode_pm_id(u64 dst_id)
-{
-	return (long)(dst_id >> PS_TYPE_BITS);
-}
-
 static inline int send_psi(int sk, u32 cmd, u32 nr_pages, u64 vaddr, u64 dst_id)
 {
 	struct page_server_iov pi = {
@@ -171,7 +168,7 @@ static int open_page_server_xfer(struct page_xfer *xfer, int fd_type, long id)
 	xfer->write_pages = write_pages_to_server;
 	xfer->write_hole = write_hole_to_server;
 	xfer->close = close_server_xfer;
-	xfer->dst_id = encode_pm_id(fd_type, id);
+	xfer->dst_id = encode_pm(fd_type, id);
 	xfer->parent = NULL;
 
 	if (send_psi(xfer->sk, PS_IOV_OPEN2, 0, 0, xfer->dst_id)) {
@@ -479,9 +476,7 @@ static int page_server_check_parent(int sk, struct page_server_iov *pi)
 	int type, ret;
 	long id;
 
-	type = decode_pm_type(pi->dst_id);
-	id = decode_pm_id(pi->dst_id);
-
+	type = decode_pm(pi->dst_id, &id);
 	if (type == -1) {
 		pr_err("Unknown pagemap type received\n");
 		return -1;
@@ -505,7 +500,7 @@ static int check_parent_server_xfer(int fd_type, long id)
 	int has_parent;
 
 	pi.cmd = PS_IOV_PARENT;
-	pi.dst_id = encode_pm_id(fd_type, id);
+	pi.dst_id = encode_pm(fd_type, id);
 
 	if (write(page_server_sk, &pi, sizeof(pi)) != sizeof(pi)) {
 		pr_perror("Can't write to page server");
@@ -552,8 +547,7 @@ static int page_server_open(int sk, struct page_server_iov *pi)
 	int type;
 	long id;
 
-	type = decode_pm_type(pi->dst_id);
-	id = decode_pm_id(pi->dst_id);
+	type = decode_pm(pi->dst_id, &id);
 	if (type == -1) {
 		pr_err("Unknown pagemap type received\n");
 		return -1;