[CRIU] [PATCH cr] restore: add helper for getting a temporary address of vma

[Andrey Vagin]

> For me it will be OK if you just use some #define or static inline helper
> titled e.g. vma_premmaped_start(vma) that will look like "return vma->shimd".

Pavel, is it what you want?

It will not be commit as this. This patch will be merged in other patches.

Signed-off-by: Andrey Vagin <avagin at openvz.org>
---
 cr-restore.c    |   33 +++++++++++++++++++--------------
 include/image.h |    1 +
 restorer.c      |    4 ++--
 3 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/cr-restore.c b/cr-restore.c
index c8cb690..2f6541f 100644
--- a/cr-restore.c
+++ b/cr-restore.c
@@ -208,7 +208,7 @@ static int map_private_vma(pid_t pid, struct vma_area *vma,
 		    p->vma.start == vma->vma.start) {
 			pr_info("COW 0x%016lx-0x%016lx 0x%016lx vma\n",
 				vma->vma.start, vma->vma.end, vma->vma.pgoff);
-			vma->vma.shmid = p->vma.shmid;
+			vma->vma.shmid = vma_entry_tmp_addr(&p->vma);
 			break;
 		}
 
@@ -216,7 +216,7 @@ static int map_private_vma(pid_t pid, struct vma_area *vma,
 
 	*pvma = list_entry(p->list.prev, struct vma_area, list);
 
-	if (!vma->vma.shmid) {
+	if (!vma_entry_tmp_addr(&vma->vma)) {
 		void *addr;
 
 		pr_info("Map 0x%016lx-0x%016lx 0x%016lx vma\n",
@@ -287,7 +287,8 @@ static int restore_anon_vma_content(pid_t pid)
 			return -1;
 		}
 
-		p = (void *) (va - vma->vma.start + vma->vma.shmid);
+		p = (void *) (va - vma->vma.start +
+					vma_entry_tmp_addr(&vma->vma));
 		if (memcmp(p, buf, PAGE_SIZE) == 0)
 			continue;
 
@@ -298,6 +299,7 @@ static int restore_anon_vma_content(pid_t pid)
 	/* Remove pages, which were not shared with a child */
 	list_for_each_entry(vma, &vma_list, list) {
 		unsigned long size, i = 0;
+		void *addr = (void *) vma_entry_tmp_addr(&vma->vma);
 
 		if (vma->ppage_bitmap == NULL)
 			continue;
@@ -310,7 +312,7 @@ static int restore_anon_vma_content(pid_t pid)
 			if ( i >= size)
 				break;
 
-			ret = madvise((void *)(vma->vma.shmid + PAGE_SIZE * i),
+			ret = madvise(addr + PAGE_SIZE * i,
 						PAGE_SIZE, MADV_DONTNEED);
 			if (ret < 0) {
 				pr_perror("madvise failed\n");
@@ -1476,6 +1478,7 @@ static int mark_target_vmas(struct list_head *self_vma_list)
 	/* Some VMA may be merged, so they are should be splitted */
 	while (&vma->list != self_vma_list) {
 		struct vma_area *c, *n;
+		unsigned long caddr;
 
 		c = NULL;
 		len++;
@@ -1483,6 +1486,7 @@ static int mark_target_vmas(struct list_head *self_vma_list)
 		/* Try to find a first target vma */
 		list_for_each_entry(n, &vma_list, list) {
 			unsigned long start = vma->vma.start;
+			unsigned long naddr = vma_entry_tmp_addr(&n->vma);
 
 			if (!vma_priv(&n->vma))
 				continue;
@@ -1490,10 +1494,11 @@ static int mark_target_vmas(struct list_head *self_vma_list)
 			if (n->vma.flags & MAP_GROWSDOWN)
 				start -= PAGE_SIZE; /* guard page */
 
-			if (n->vma.shmid >= start &&
-			    n->vma.shmid < vma->vma.end &&
-			    (c == NULL || c->vma.shmid > n->vma.shmid))
+			if (naddr >= start && naddr < vma->vma.end &&
+			    (c == NULL || caddr > naddr)) {
 				c = n;
+				caddr = naddr;
+			}
 		}
 
 		if (c == NULL) {
@@ -1504,20 +1509,20 @@ static int mark_target_vmas(struct list_head *self_vma_list)
 		}
 
 		pr_debug("Mark VMA 0x%016lx-0x%016lx inside 0x%016lx-0x%016lx\n",
-				c->vma.shmid, c->vma.shmid + vma_area_len(c),
+				caddr, caddr + vma_area_len(c),
 				vma->vma.start, vma->vma.end);
 
 		/* A first part isn't a target VMA */
-		if (c->vma.shmid > vma->vma.start) {
+		if (caddr > vma->vma.start) {
 			BUG_ON(c->vma.flags & MAP_GROWSDOWN);
 			new = alloc_vma_area();
 			if (new == NULL)
 				return -1;
 			memcpy(new, vma, sizeof(*vma));
 
-			vma->vma.start = c->vma.shmid;
+			vma->vma.start = caddr;
 
-			new->vma.end = c->vma.shmid;
+			new->vma.end = caddr;
 			list_add(&new->list, &new_list);
 			len++;
 		}
@@ -1526,15 +1531,15 @@ static int mark_target_vmas(struct list_head *self_vma_list)
 			vma->vma.start -= PAGE_SIZE; /* guard page */
 
 		/* Split a target VMA and handle a remaining part again */
-		if (c->vma.shmid + vma_area_len(c) < vma->vma.end) {
+		if (caddr + vma_area_len(c) < vma->vma.end) {
 			new = alloc_vma_area();
 			if (new == NULL)
 				return -1;
 			memcpy(new, vma, sizeof(*vma));
 
-			new->vma.start = c->vma.shmid + vma_area_len(c);
+			new->vma.start = caddr + vma_area_len(c);
 
-			vma->vma.end = c->vma.shmid + vma_area_len(c);
+			vma->vma.end = caddr + vma_area_len(c);
 			vma->vma.status |= VMA_AREA_DEST;
 			list_move_tail(&vma->list, &new_list);
 
diff --git a/include/image.h b/include/image.h
index 4fb4eab..616badc 100644
--- a/include/image.h
+++ b/include/image.h
@@ -95,6 +95,7 @@
 
 #define VMA_AREA_DEST		(1 <<  11)
 
+#define vma_entry_tmp_addr(vma) ((vma)->shmid)
 #define vma_entry_is(vma, s)	(((vma)->status & (s)) == (s))
 #define vma_entry_len(vma)	((vma)->end - (vma)->start)
 
diff --git a/restorer.c b/restorer.c
index 48aef03..3d21f83 100644
--- a/restorer.c
+++ b/restorer.c
@@ -340,12 +340,12 @@ long __export_restore_task(struct task_restore_core_args *args)
 		if (!vma_priv(vma_entry))
 			continue;
 
-		va = sys_mremap(vma_entry->shmid,
+		va = sys_mremap(vma_entry_tmp_addr(vma_entry),
 				vma_entry_len(vma_entry), vma_entry_len(vma_entry),
 				MREMAP_MAYMOVE | MREMAP_FIXED, vma_entry->start);
 		if (va != vma_entry->start) {
 			pr_err("Unable to remap %lx -> %lx mapping with %lx\n",
-				vma_entry->shmid, vma_entry->start, va);
+				vma_entry_tmp_addr(vma_entry), vma_entry->start, va);
 			goto core_restore_end;
 		}
 	}
-- 
1.7.1