[CRIU] [PATCH 1/5] page-server: Introduce page_server_start_sync_read

[Pavel Emelyanov]

There's no need in two API calls to read xfer header
and pages themselves, so merge them into one single
call.

Signed-off-by: Pavel Emelyanov <xemul at virtuozzo.com>
---
 criu/include/page-xfer.h |  3 +--
 criu/page-xfer.c         | 22 ++++++++++++++++++++--
 criu/pagemap.c           | 14 ++------------
 3 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/criu/include/page-xfer.h b/criu/include/page-xfer.h
index 0b92ec9..5d8dc81 100644
--- a/criu/include/page-xfer.h
+++ b/criu/include/page-xfer.h
@@ -60,11 +60,10 @@ extern int check_parent_page_xfer(int fd_type, long id);
 
 /* async request/receive of remote pages */
 extern int request_remote_pages(int pid, unsigned long addr, int nr_pages);
-extern int receive_remote_pages_info(int *nr_pages, unsigned long *addr, int *pid);
-extern int receive_remote_pages(int len, void *buf);
 
 typedef int (*ps_async_read_complete)(int pid, unsigned long vaddr, int nr_pages, void *);
 extern int page_server_start_async_read(void *buf, int nr_pages,
 		ps_async_read_complete complete, void *priv);
+extern int page_server_start_sync_read(void *buf, int nr_pages, unsigned long *vaddr);
 
 #endif /* __CR_PAGE_XFER__H__ */
diff --git a/criu/page-xfer.c b/criu/page-xfer.c
index c557407..761985a 100644
--- a/criu/page-xfer.c
+++ b/criu/page-xfer.c
@@ -1174,7 +1174,7 @@ int request_remote_pages(int pid, unsigned long addr, int nr_pages)
 	return 0;
 }
 
-int receive_remote_pages_info(int *nr_pages, unsigned long *addr, int *pid)
+static int receive_remote_pages_info(int *nr_pages, unsigned long *addr, int *pid)
 {
 	struct page_server_iov pi;
 
@@ -1194,7 +1194,7 @@ int receive_remote_pages_info(int *nr_pages, unsigned long *addr, int *pid)
 	return 0;
 }
 
-int receive_remote_pages(int len, void *buf)
+static int receive_remote_pages(int len, void *buf)
 {
 	if (recv(page_server_sk, buf, len, MSG_WAITALL) != len) {
 		pr_perror("Failed to receive page data");
@@ -1203,3 +1203,21 @@ int receive_remote_pages(int len, void *buf)
 
 	return 0;
 }
+
+int page_server_start_sync_read(void *buf, int nr, unsigned long *vaddr)
+{
+	int ret, pid, new_nr;
+
+	/*
+	 * Note, that for async remote page_read, the actual
+	 * transfer happens in the lazy-pages daemon
+	 */
+	ret = receive_remote_pages_info(&new_nr, vaddr, &pid);
+	if (ret == 0) {
+		if (new_nr < 0 || new_nr > nr)
+			return -1;
+		ret = receive_remote_pages(nr * PAGE_SIZE, buf);
+	}
+
+	return ret;
+}
diff --git a/criu/pagemap.c b/criu/pagemap.c
index d770e81..06264a1 100644
--- a/criu/pagemap.c
+++ b/criu/pagemap.c
@@ -466,7 +466,7 @@ static int read_page_complete(int pid, unsigned long vaddr, int nr_pages, void *
 static int maybe_read_page_remote(struct page_read *pr, unsigned long vaddr,
 				  int nr, void *buf, unsigned flags)
 {
-	int ret, pid, new_nr;
+	int ret;
 
 	/* We always do PR_ASAP mode here (FIXME?) */
 	ret = request_remote_pages(pr->pid, vaddr, nr);
@@ -475,17 +475,7 @@ static int maybe_read_page_remote(struct page_read *pr, unsigned long vaddr,
 	if (flags & PR_ASYNC)
 		return page_server_start_async_read(buf, nr, read_page_complete, pr);
 
-	/*
-	 * Note, that for async remote page_read, the actual
-	 * transfer happens in the lazy-pages daemon
-	 */
-	ret = receive_remote_pages_info(&new_nr, &vaddr, &pid);
-	if (ret == 0) {
-		if (new_nr < 0 || new_nr > nr)
-			return -1;
-		ret = receive_remote_pages(nr * PAGE_SIZE, buf);
-	}
-
+	ret = page_server_start_sync_read(buf, nr, &vaddr);
 	if (ret == 0 && pr->io_complete)
 		ret = pr->io_complete(pr, vaddr, nr);
 
-- 
2.1.4