page-xfer: dump compatible iovec

Change page_xfer_dump_pages the way it could handle compatible iovs.
Separated hole dumping in page_xfer_dump_hole and introduced
iterator function get_iov which will return native iovec,
converting compatible iovec if needed.

Fixes:
(00.009060) Fetched ack: 7 7 0
(00.009061) Transfering pages:
(00.009062) 	buf 16/16
(00.009063) 	p 0x100008048000 [32841]
(00.009101) Error (page-xfer.c:504): Only 65536 of 17592320561152 bytes have been spliced
(00.009253) page-pipe: Killing page pipe
(00.009263) ----------------------------------------

Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/include/page-pipe.h

@@ -119,6 +119,12 @@ struct page_pipe {
 #define PP_COMPAT	0x2	/* Use compatible iovs (struct compat_iovec) */
 #define PP_OWN_IOVS	0x4	/* create_page_pipe allocated IOVs memory */
 
+/* XXX: move to arch-depended file, when non-x86 add support for compat mode */
+struct iovec_compat {
+	u32	iov_base;
+	u32	iov_len;
+};
+
 struct page_pipe *create_page_pipe(unsigned int nr_segs, struct iovec *iovs, unsigned flags);
 extern void destroy_page_pipe(struct page_pipe *p);
 extern int page_pipe_add_page(struct page_pipe *p, unsigned long addr);

criu/page-pipe.c

@@ -81,12 +81,6 @@ static int ppb_resize_pipe(struct page_pipe_buf *ppb, unsigned long new_size)
 	return 0;
 }
 
-/* XXX: move to arch-depended file, when non-x86 add support for compat mode */
-struct iovec_compat {
-	u32	iov_base;
-	u32	iov_len;
-};
-
 static inline void iov_init_compat(struct iovec_compat *iov, unsigned long addr)
 {
 	iov->iov_base = (u32)addr;

criu/page-xfer.c

@@ -341,9 +341,19 @@ static int page_xfer_dump_hole(struct page_xfer *xfer,
 	return 0;
 }
 
-static struct iovec get_iov(struct iovec *iovs, unsigned int n)
+static struct iovec get_iov(struct iovec *iovs, unsigned int n, bool compat)
 {
+	if (likely(!compat)) {
 		return iovs[n];
+	} else {
+		struct iovec ret;
+		struct iovec_compat *tmp = (struct iovec_compat*)(void *)iovs;
+
+		tmp += n;
+		ret.iov_base = (void *)(uintptr_t)tmp->iov_base;
+		ret.iov_len = tmp->iov_len;
+		return ret;
+	}
 }
 
 static int dump_holes(struct page_xfer *xfer, struct page_pipe *pp,
@@ -352,7 +362,8 @@ static int dump_holes(struct page_xfer *xfer, struct page_pipe *pp,
 	int ret;
 
 	for (; *cur_hole < pp->free_hole ; (*cur_hole)++) {
-		struct iovec hole = get_iov(pp->holes, *cur_hole);
+		struct iovec hole = get_iov(pp->holes, *cur_hole,
+						pp->flags & PP_COMPAT);
 
 		if (limit && hole.iov_base >= limit)
 			break;
@@ -380,7 +391,7 @@ int page_xfer_dump_pages(struct page_xfer *xfer, struct page_pipe *pp,
 		pr_debug("\tbuf %d/%d\n", ppb->pages_in, ppb->nr_segs);
 
 		for (i = 0; i < ppb->nr_segs; i++) {
-			struct iovec iov = get_iov(ppb->iov, i);
+			struct iovec iov = get_iov(ppb->iov, i, pp->flags & PP_COMPAT);
 
 			ret = dump_holes(xfer, pp, &cur_hole, iov.iov_base, off);
 			if (ret)