criu: pagemap: drop put_pagemap

With in-memory pagemap put_pagemap is not required because it does not
frees any resources. Minor modifications to get_pagemap and init_pagemaps
allow proper bookkeeping without put_pagemap.
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/cr-dedup.c

@@ -83,22 +83,17 @@ static int cr_dedup_one_pagemap(int id, int flags)
 	if (!prp)
 		goto exit;
 
-	ret = pr.get_pagemap(&pr, &iov);
-	if (ret <= 0)
-		goto exit;
-
 	while (1) {
+		ret = pr.get_pagemap(&pr, &iov);
+		if (ret <= 0)
+			goto exit;
+
 		pr_debug("dedup iovec base=%p, len=%zu\n", iov.iov_base, iov.iov_len);
 		if (!pr.pe->in_parent) {
 			ret = dedup_one_iovec(prp, &iov);
 			if (ret)
 				goto exit;
 		}
-
-		pr.put_pagemap(&pr);
-		ret = pr.get_pagemap(&pr, &iov);
-		if (ret <= 0)
-			goto exit;
 	}
 exit:
 	pr.close(&pr);

criu/include/pagemap.h

@@ -48,8 +48,6 @@ struct page_read {
 	int (*get_pagemap)(struct page_read *, struct iovec *iov);
 	/* reads page from current pagemap */
 	int (*read_pages)(struct page_read *, unsigned long vaddr, int nr, void *);
-	/* stop working on current pagemap */
-	void (*put_pagemap)(struct page_read *);
 	void (*close)(struct page_read *);
 	int (*seek_page)(struct page_read *pr, unsigned long vaddr, bool warn);
 

criu/mem.c

@@ -788,9 +788,6 @@ static int restore_priv_vma_content(struct pstree_item *t)
 			}
 
 		}
-
-		if (pr.put_pagemap)
-			pr.put_pagemap(&pr);
 	}
 
 err_read:

criu/pagemap.c

@@ -127,6 +127,7 @@ static int get_pagemap(struct page_read *pr, struct iovec *iov)
 {
 	PagemapEntry *pe;
 
+	pr->curr_pme++;
 	if (pr->curr_pme >= pr->nr_pmes)
 		return 0;
 
@@ -145,11 +146,6 @@ static int get_pagemap(struct page_read *pr, struct iovec *iov)
 	return 1;
 }
 
-static void put_pagemap(struct page_read *pr)
-{
-	pr->curr_pme++;
-}
-
 static void skip_pagemap_pages(struct page_read *pr, unsigned long len)
 {
 	if (!len)
@@ -185,7 +181,6 @@ static int seek_pagemap_page(struct page_read *pr, unsigned long vaddr,
 
 		if (iov_end <= vaddr) {
 			skip_pagemap_pages(pr, iov_end - pr->cvaddr);
-			put_pagemap(pr);
 new_pagemap:
 			ret = get_pagemap(pr, &iov);
 			if (ret <= 0)
@@ -397,7 +392,8 @@ static int init_pagemaps(struct page_read *pr)
 	if (!pr->pmes)
 		return -1;
 
-	pr->nr_pmes = pr->curr_pme = 0;
+	pr->nr_pmes = 0;
+	pr->curr_pme = -1;
 
 	while (1) {
 		int ret = pb_read_one_eof(pr->pmi, &pr->pmes[pr->nr_pmes],
@@ -485,7 +481,6 @@ int open_page_read_at(int dfd, int pid, struct page_read *pr, int pr_flags)
 	}
 
 	pr->get_pagemap = get_pagemap;
-	pr->put_pagemap = put_pagemap;
 	pr->read_pages = read_pagemap_page;
 	pr->close = close_page_read;
 	pr->seek_page = seek_pagemap_page;

criu/shmem.c

@@ -481,9 +481,6 @@ static int restore_shmem_content(void *addr, struct shmem_info *si)
 			break;
 
 		pr.read_pages(&pr, vaddr, nr_pages, addr + vaddr);
-
-		if (pr.put_pagemap)
-			pr.put_pagemap(&pr);
 	}
 
 	pr.close(&pr);