xfer: Change ->write_hole's type to flags

The ->write_hole and ->write_pagemap now look very much
alike, so let's merge them. This is preparatory patch
that makes holy type decision based on PE_FOO flags.
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>

criu/include/page-xfer.h

@@ -16,7 +16,7 @@ struct page_xfer {
 	/* transfers pages related to previous pagemap */
 	int (*write_pages)(struct page_xfer *self, int pipe, unsigned long len);
 	/* transfers one hole -- vaddr:len entry w/o pages */
-	int (*write_hole)(struct page_xfer *self, struct iovec *iov, int type);
+	int (*write_hole)(struct page_xfer *self, struct iovec *iov, u32 flags);
 	void (*close)(struct page_xfer *self);
 
 	/* private data for every page-xfer engine */

criu/page-xfer.c

@@ -173,10 +173,21 @@ static int write_pages_to_server(struct page_xfer *xfer,
 	return 0;
 }
 
-static int write_hole_to_server(struct page_xfer *xfer, struct iovec *iov,
-				int type)
+static int write_hole_to_server(struct page_xfer *xfer, struct iovec *iov, u32 flags)
 {
-	return send_iov(xfer->sk, type, xfer->dst_id, iov);
+	u32 cmd = 0;
+	BUG_ON(flags & PE_PRESENT);
+
+	if (flags & PE_PARENT)
+		cmd = PS_IOV_HOLE;
+	else if (flags & PE_LAZY)
+		cmd = PS_IOV_LAZY;
+	else if (flags & PE_ZERO)
+		cmd = PS_IOV_ZERO;
+	else
+		BUG();
+
+	return send_iov(xfer->sk, cmd, xfer->dst_id, iov);
 }
 
 static void close_server_xfer(struct page_xfer *xfer)
@@ -303,16 +314,18 @@ static int check_pagehole_in_parent(struct page_read *p, struct iovec *iov)
 	}
 }
 
-static int write_hole_loc(struct page_xfer *xfer, struct iovec *iov, int type)
+static int write_hole_loc(struct page_xfer *xfer, struct iovec *iov, u32 flags)
 {
 	PagemapEntry pe = PAGEMAP_ENTRY__INIT;
 
+	BUG_ON(flags & PE_PRESENT);
+
 	pe.vaddr = encode_pointer(iov->iov_base);
 	pe.nr_pages = iov->iov_len / PAGE_SIZE;
 	pe.has_flags = true;
+	pe.flags = flags;
 
-	switch (type) {
-	case PS_IOV_HOLE:
+	if (flags & PE_PARENT) {
 		if (xfer->parent != NULL) {
 			int ret;
 
@@ -323,16 +336,6 @@ static int write_hole_loc(struct page_xfer *xfer, struct iovec *iov, int type)
 				return -1;
 			}
 		}
-		pe.flags |= PE_PARENT;
-		break;
-	case PS_IOV_ZERO:
-		pe.flags |= PE_ZERO;
-		break;
-	case PS_IOV_LAZY:
-		pe.flags |= PE_LAZY;
-		break;
-	default:
-		return -1;
 	}
 
 	if (pb_write_one(xfer->pmi, &pe, PB_PAGEMAP) < 0)
@@ -417,27 +420,27 @@ int open_page_xfer(struct page_xfer *xfer, int fd_type, long id)
 }
 
 static int page_xfer_dump_hole(struct page_xfer *xfer,
-			       struct iovec *hole, unsigned long off, int type)
+			       struct iovec *hole, unsigned long off, u32 flags)
 {
 	BUG_ON(hole->iov_base < (void *)off);
 	hole->iov_base -= off;
 	pr_debug("\th %p [%u]\n", hole->iov_base,
 			(unsigned int)(hole->iov_len / PAGE_SIZE));
 
-	if (xfer->write_hole(xfer, hole, type))
+	if (xfer->write_hole(xfer, hole, flags))
 		return -1;
 
 	return 0;
 }
 
-static int get_hole_type(struct page_pipe *pp, int n)
+static int get_hole_flags(struct page_pipe *pp, int n)
 {
 	unsigned int hole_flags = pp->hole_flags[n];
 
 	if (hole_flags == PP_HOLE_PARENT)
-		return PS_IOV_HOLE;
+		return PE_PARENT;
 	if (hole_flags == PP_HOLE_ZERO)
-		return PS_IOV_ZERO;
+		return PE_ZERO;
 	else
 		BUG();
 
@@ -451,12 +454,13 @@ static int dump_holes(struct page_xfer *xfer, struct page_pipe *pp,
 
 	for (; *cur_hole < pp->free_hole ; (*cur_hole)++) {
 		struct iovec hole = pp->holes[*cur_hole];
-		int hole_type = get_hole_type(pp, *cur_hole);
+		u32 hole_flags;
 
 		if (limit && hole.iov_base >= limit)
 			break;
 
-		ret = page_xfer_dump_hole(xfer, &hole, off, hole_type);
+		hole_flags = get_hole_flags(pp, *cur_hole);
+		ret = page_xfer_dump_hole(xfer, &hole, off, hole_flags);
 		if (ret)
 			return ret;
 	}
@@ -493,8 +497,7 @@ int page_xfer_dump_pages(struct page_xfer *xfer, struct page_pipe *pp,
 
 			if (ppb->flags & PPB_LAZY) {
 				if (!dump_lazy) {
-					if (xfer->write_hole(xfer, &iov,
-							     PS_IOV_LAZY))
+					if (xfer->write_hole(xfer, &iov, PE_LAZY))
 						return -1;
 					continue;
 				} else {
@@ -712,7 +715,7 @@ static int page_server_add(int sk, struct page_server_iov *pi)
 	return 0;
 }
 
-static int page_server_hole(int sk, struct page_server_iov *pi)
+static int page_server_hole(int sk, struct page_server_iov *pi, u32 flags)
 {
 	struct page_xfer *lxfer = &cxfer.loc_xfer;
 	struct iovec iov;
@@ -723,7 +726,7 @@ static int page_server_hole(int sk, struct page_server_iov *pi)
 		return -1;
 
 	psi2iovec(pi, &iov);
-	if (lxfer->write_hole(lxfer, &iov, pi->cmd))
+	if (lxfer->write_hole(lxfer, &iov, flags))
 		return -1;
 
 	return 0;
@@ -827,9 +830,13 @@ static int page_server_serve(int sk)
 			ret = page_server_add(sk, &pi);
 			break;
 		case PS_IOV_HOLE:
+			ret = page_server_hole(sk, &pi, PE_PARENT);
+			break;
 		case PS_IOV_ZERO:
+			ret = page_server_hole(sk, &pi, PE_ZERO);
+			break;
 		case PS_IOV_LAZY:
-			ret = page_server_hole(sk, &pi);
+			ret = page_server_hole(sk, &pi, PE_LAZY);
 			break;
 		case PS_IOV_FLUSH:
 		case PS_IOV_FLUSH_N_CLOSE: