[CRIU] [PATCH 1/6] criu: pagemap: drop put_pagemap

[Mike Rapoport]

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 at linux.vnet.ibm.com>
---
 criu/cr-dedup.c        | 13 ++++---------
 criu/include/pagemap.h |  2 --
 criu/mem.c             |  3 ---
 criu/pagemap.c         | 14 ++++----------
 criu/shmem.c           |  3 ---
 criu/uffd.c            |  3 ---
 6 files changed, 8 insertions(+), 30 deletions(-)

diff --git a/criu/cr-dedup.c b/criu/cr-dedup.c
index 527a6b6..cc44152 100644
--- a/criu/cr-dedup.c
+++ b/criu/cr-dedup.c
@@ -82,22 +82,17 @@ 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);
diff --git a/criu/include/pagemap.h b/criu/include/pagemap.h
index 81ff96b..f45b2a9 100644
--- a/criu/include/pagemap.h
+++ b/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 *);
 	void (*skip_pages)(struct page_read *, unsigned long len);
 	int (*seek_page)(struct page_read *pr, unsigned long vaddr, bool warn);
diff --git a/criu/mem.c b/criu/mem.c
index 63acec3..1c01a09 100644
--- a/criu/mem.c
+++ b/criu/mem.c
@@ -804,9 +804,6 @@ static int restore_priv_vma_content(struct pstree_item *t)
 			}
 
 		}
-
-		if (pr.put_pagemap)
-			pr.put_pagemap(&pr);
 	}
 
 err_read:
diff --git a/criu/pagemap.c b/criu/pagemap.c
index 86591e4..d8fe5b0 100644
--- a/criu/pagemap.c
+++ b/criu/pagemap.c
@@ -121,16 +121,12 @@ int dedup_one_iovec(struct page_read *pr, struct iovec *iov)
 	return 0;
 }
 
-static void put_pagemap(struct page_read *pr)
-{
-	pr->curr_pme++;
-}
-
 static int get_pagemap(struct page_read *pr, struct iovec *iov)
 {
 	PagemapEntry *pe;
 
 	for (;;) {
+		pr->curr_pme++;
 		if (pr->curr_pme >= pr->nr_pmes)
 			return 0;
 
@@ -138,7 +134,6 @@ static int get_pagemap(struct page_read *pr, struct iovec *iov)
 
 		if (!pe->zero)
 			break;
-		put_pagemap(pr);
 	}
 
 	pagemap2iovec(pe, iov);
@@ -189,7 +184,6 @@ 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)
@@ -331,7 +325,7 @@ static void reset_pagemap(struct page_read *pr)
 {
 	pr->cvaddr = 0;
 	pr->pi_off = 0;
-	pr->curr_pme = 0;
+	pr->curr_pme = -1;
 	pr->pe = NULL;
 
 	/* FIXME: take care of bunch */
@@ -398,7 +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],
@@ -486,7 +481,6 @@ int open_page_read_at(int dfd, int id, 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->skip_pages = skip_pagemap_pages;
diff --git a/criu/shmem.c b/criu/shmem.c
index c422b4c..341e3bc 100644
--- a/criu/shmem.c
+++ b/criu/shmem.c
@@ -452,9 +452,6 @@ 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);
diff --git a/criu/uffd.c b/criu/uffd.c
index cf03c31..97cacea 100644
--- a/criu/uffd.c
+++ b/criu/uffd.c
@@ -490,9 +490,6 @@ static int collect_uffd_pages(struct page_read *pr, struct lazy_pages_info *lpi)
 	base = (unsigned long) iov.iov_base;
 	pr_debug("iov.iov_base 0x%lx (%ld pages)\n", base, nr_pages);
 
-	if (pr->put_pagemap)
-		pr->put_pagemap(pr);
-
 	for (i = 0; i < nr_pages; i++) {
 		bool uffd_page = false;
 		base = (unsigned long) iov.iov_base + (i * ps);
-- 
1.9.1