[CRIU] [PATCH 08/16] mem/vma: Sanitize struct vm_area_list

[Cyrill Gorcunov]

 - make names more descriptive
 - add comments
 - use union for nr_priv_pages and rst_priv_size since
   former priv_size has been used with different meaning:
   number of pages during checkpoint time and size in bytes
   on restore moment

Signed-off-by: Cyrill Gorcunov <gorcunov at gmail.com>
---
 criu/cr-dump.c     |  2 +-
 criu/include/vma.h | 15 +++++++++------
 criu/mem.c         | 20 ++++++++++----------
 criu/proc_parse.c  |  9 +++++----
 4 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/criu/cr-dump.c b/criu/cr-dump.c
index 9b891497b53f..bea86b618c48 100644
--- a/criu/cr-dump.c
+++ b/criu/cr-dump.c
@@ -126,7 +126,7 @@ int collect_mappings(pid_t pid, struct vm_area_list *vma_area_list,
 		goto err;
 
 	pr_info("Collected, longest area occupies %lu pages\n",
-			vma_area_list->priv_longest);
+		vma_area_list->nr_priv_pages_longest);
 	pr_info_vma_list(&vma_area_list->h);
 
 	pr_info("----------------------------------------\n");
diff --git a/criu/include/vma.h b/criu/include/vma.h
index 3cdd1b319561..5e3f3527bf01 100644
--- a/criu/include/vma.h
+++ b/criu/include/vma.h
@@ -10,12 +10,15 @@
 #include <string.h>
 
 struct vm_area_list {
-	struct list_head	h;
-	unsigned		nr;
-	unsigned int		nr_aios;
-	unsigned long		priv_size; /* nr of pages in private VMAs */
-	unsigned long		priv_longest; /* nr of pages in longest private VMA */
-	unsigned long		shared_longest; /* nr of pages in longest shared VMA */
+	struct list_head	h;			/* list of VMAs */
+	unsigned		nr;			/* nr of all VMAs in the list */
+	unsigned int		nr_aios;		/* nr of AIOs VMAs in the list */
+	union {
+		unsigned long	nr_priv_pages;		/* dmp: nr of pages in private VMAs */
+		unsigned long	rst_priv_size;		/* rst: size of private VMAs */
+	};
+	unsigned long		nr_priv_pages_longest;	/* nr of pages in longest private VMA */
+	unsigned long		nr_shared_pages_longest;/* nr of pages in longest shared VMA */
 };
 
 static inline void vm_area_list_init(struct vm_area_list *vml)
diff --git a/criu/mem.c b/criu/mem.c
index 6a1a87a1e593..e7eccaffbece 100644
--- a/criu/mem.c
+++ b/criu/mem.c
@@ -81,7 +81,7 @@ unsigned long dump_pages_args_size(struct vm_area_list *vmas)
 	/* In the worst case I need one iovec for each page */
 	return sizeof(struct parasite_dump_pages_args) +
 		vmas->nr * sizeof(struct parasite_vma_entry) +
-		(vmas->priv_size + 1) * sizeof(struct iovec);
+		(vmas->nr_priv_pages + 1) * sizeof(struct iovec);
 }
 
 static inline bool __page_is_zero(u64 pme)
@@ -414,14 +414,14 @@ static int __parasite_dump_pages_seized(struct pstree_item *item,
 	timing_start(TIME_MEMDUMP);
 
 	pr_debug("   Private vmas %lu/%lu pages\n",
-			vma_area_list->priv_longest, vma_area_list->priv_size);
+		 vma_area_list->nr_priv_pages_longest, vma_area_list->nr_priv_pages);
 
 	/*
 	 * Step 0 -- prepare
 	 */
 
-	pmc_size = max(vma_area_list->priv_longest,
-		vma_area_list->shared_longest);
+	pmc_size = max(vma_area_list->nr_priv_pages_longest,
+		       vma_area_list->nr_shared_pages_longest);
 	if (pmc_init(&pmc, item->pid->real, &vma_area_list->h,
 			 pmc_size * PAGE_SIZE))
 		return -1;
@@ -433,7 +433,7 @@ static int __parasite_dump_pages_seized(struct pstree_item *item,
 		 * use, i.e. on non-lazy non-predump.
 		 */
 		cpp_flags |= PP_CHUNK_MODE;
-	pp = create_page_pipe(vma_area_list->priv_size,
+	pp = create_page_pipe(vma_area_list->nr_priv_pages,
 					    mdc->lazy ? NULL : pargs_iovs(args),
 					    cpp_flags);
 	if (!pp)
@@ -612,9 +612,9 @@ int prepare_mm_pid(struct pstree_item *i)
 		list_add_tail(&vma->list, &ri->vmas.h);
 
 		if (vma_area_is_private(vma, kdat.task_size)) {
-			ri->vmas.priv_size += vma_area_len(vma);
+			ri->vmas.rst_priv_size += vma_area_len(vma);
 			if (vma_has_guard_gap_hidden(vma))
-				ri->vmas.priv_size += PAGE_SIZE;
+				ri->vmas.rst_priv_size += PAGE_SIZE;
 		}
 
 		pr_info("vma 0x%"PRIx64" 0x%"PRIx64"\n", vma->e->start, vma->e->end);
@@ -1171,17 +1171,17 @@ int prepare_mappings(struct pstree_item *t)
 		goto out;
 
 	/* Reserve a place for mapping private vma-s one by one */
-	addr = mmap(NULL, vmas->priv_size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+	addr = mmap(NULL, vmas->rst_priv_size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
 	if (addr == MAP_FAILED) {
 		ret = -1;
-		pr_perror("Unable to reserve memory (%lu bytes)", vmas->priv_size);
+		pr_perror("Unable to reserve memory (%lu bytes)", vmas->rst_priv_size);
 		goto out;
 	}
 
 	old_premmapped_addr = rsti(t)->premmapped_addr;
 	old_premmapped_len = rsti(t)->premmapped_len;
 	rsti(t)->premmapped_addr = addr;
-	rsti(t)->premmapped_len = vmas->priv_size;
+	rsti(t)->premmapped_len = vmas->rst_priv_size;
 
 	ret = open_page_read(vpid(t), &pr, PR_TASK);
 	if (ret <= 0)
diff --git a/criu/proc_parse.c b/criu/proc_parse.c
index 4c127f264062..0e8b6f209f3c 100644
--- a/criu/proc_parse.c
+++ b/criu/proc_parse.c
@@ -660,14 +660,15 @@ static int vma_list_add(struct vma_area *vma_area,
 		unsigned long pages;
 
 		pages = vma_area_len(vma_area) / PAGE_SIZE;
-		vma_area_list->priv_size += pages;
-		vma_area_list->priv_longest = max(vma_area_list->priv_longest, pages);
+		vma_area_list->nr_priv_pages += pages;
+		vma_area_list->nr_priv_pages_longest =
+			max(vma_area_list->nr_priv_pages_longest, pages);
 	} else if (vma_area_is(vma_area, VMA_ANON_SHARED)) {
 		unsigned long pages;
 
 		pages = vma_area_len(vma_area) / PAGE_SIZE;
-		vma_area_list->shared_longest =
-			max(vma_area_list->shared_longest, pages);
+		vma_area_list->nr_shared_pages_longest =
+			max(vma_area_list->nr_shared_pages_longest, pages);
 	}
 
 	*prev_vfi = *vfi;
-- 
2.20.1