[CRIU] [PATCHv3 14/30] page-xfer: dump compatible iovec

[Dmitry Safonov]

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 at openvz.org>
Signed-off-by: Dmitry Safonov <dsafonov at virtuozzo.com>
---
 criu/include/page-pipe.h |  6 ++++
 criu/page-pipe.c         |  6 ----
 criu/page-xfer.c         | 88 +++++++++++++++++++++++++++++-------------------
 3 files changed, 60 insertions(+), 40 deletions(-)

diff --git a/criu/include/page-pipe.h b/criu/include/page-pipe.h
index 19e7a898e77f..474ffa004daa 100644
--- a/criu/include/page-pipe.h
+++ b/criu/include/page-pipe.h
@@ -98,6 +98,12 @@ struct page_pipe {
 	bool compat_iov;	/* Use compatible iovs (struct compat_iovec) */
 };
 
+/* XXX: move to arch-depended file, when non-x86 add support for compat mode */
+struct iovec_compat {
+	u32	iov_base;
+	u32	iov_len;
+};
+
 extern struct page_pipe *create_page_pipe(unsigned int nr, struct iovec *,
 					bool chunk_mode, bool compat_iov);
 extern void destroy_page_pipe(struct page_pipe *p);
diff --git a/criu/page-pipe.c b/criu/page-pipe.c
index c38b96e89407..db597b27f1e2 100644
--- a/criu/page-pipe.c
+++ b/criu/page-pipe.c
@@ -100,12 +100,6 @@ static struct page_pipe_buf *ppb_alloc_resize(struct page_pipe *pp, int size)
 	return ppb;
 }
 
-/* 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;
diff --git a/criu/page-xfer.c b/criu/page-xfer.c
index 3813712fefcf..8c2c799c0b0f 100644
--- a/criu/page-xfer.c
+++ b/criu/page-xfer.c
@@ -320,61 +320,81 @@ int open_page_xfer(struct page_xfer *xfer, int fd_type, long id)
 		return open_page_local_xfer(xfer, fd_type, id);
 }
 
+static int page_xfer_dump_hole(struct page_xfer *xfer,
+		struct iovec *hole, unsigned long off)
+{
+	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))
+		return -1;
+
+	return 0;
+}
+
+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;
+	}
+}
+
 int page_xfer_dump_pages(struct page_xfer *xfer, struct page_pipe *pp,
 		unsigned long off)
 {
 	struct page_pipe_buf *ppb;
-	struct iovec *hole = NULL;
+	unsigned int cur_hole = 0;
+	int ret;
 
 	pr_debug("Transfering pages:\n");
 
-	if (pp->free_hole)
-		hole = &pp->holes[0];
-
 	list_for_each_entry(ppb, &pp->bufs, l) {
-		int i;
+		unsigned int i;
 
 		pr_debug("\tbuf %d/%d\n", ppb->pages_in, ppb->nr_segs);
 
 		for (i = 0; i < ppb->nr_segs; i++) {
-			struct iovec *iov = &ppb->iov[i];
-
-			while (hole && (hole->iov_base < iov->iov_base)) {
-				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))
-					return -1;
-
-				hole++;
-				if (hole >= &pp->holes[pp->free_hole])
-					hole = NULL;
+			struct iovec iov = get_iov(ppb->iov, i, pp->compat_iov);
+
+			for (; cur_hole < pp->free_hole ; cur_hole++) {
+				struct iovec hole = get_iov(pp->holes, cur_hole,
+						pp->compat_iov);
+
+				if (hole.iov_base < iov.iov_base)
+					break;
+				ret = page_xfer_dump_hole(xfer, &hole, off);
+				if (ret)
+					return ret;
 			}
 
-			BUG_ON(iov->iov_base < (void *)off);
-			iov->iov_base -= off;
-			pr_debug("\tp %p [%u]\n", iov->iov_base,
-					(unsigned int)(iov->iov_len / PAGE_SIZE));
+			BUG_ON(iov.iov_base < (void *)off);
+			iov.iov_base -= off;
+			pr_debug("\tp %p [%u]\n", iov.iov_base,
+					(unsigned int)(iov.iov_len / PAGE_SIZE));
 
-			if (xfer->write_pagemap(xfer, iov))
+			if (xfer->write_pagemap(xfer, &iov))
 				return -1;
-			if (xfer->write_pages(xfer, ppb->p[0], iov->iov_len))
+			if (xfer->write_pages(xfer, ppb->p[0], iov.iov_len))
 				return -1;
 		}
 	}
 
-	while (hole) {
-		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))
-			return -1;
+	for (; cur_hole < pp->free_hole ; cur_hole++) {
+		struct iovec hole = get_iov(pp->holes, cur_hole, pp->compat_iov);
 
-		hole++;
-		if (hole >= &pp->holes[pp->free_hole])
-			hole = NULL;
+		ret = page_xfer_dump_hole(xfer, &hole, off);
+		if (ret)
+			return ret;
 	}
 
 	return 0;
-- 
2.9.0