[CRIU] [PATCH 1/3] criu: pagemap: track current offset into pages*img

[Mike Rapoport]

instead if doing lseek

Signed-off-by: Mike Rapoport <rppt at linux.vnet.ibm.com>
---
 criu/include/pagemap.h |  1 +
 criu/pagemap.c         | 12 +++++++-----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/criu/include/pagemap.h b/criu/include/pagemap.h
index 0c731ce..5e6c4b2 100644
--- a/criu/include/pagemap.h
+++ b/criu/include/pagemap.h
@@ -64,6 +64,7 @@ struct page_read {
 					   go to this guy for page, see
 					   read_pagemap_page */
 	unsigned long cvaddr;		/* vaddr we are on */
+	off_t pi_off;			/* current offset in pages file */
 
 	struct iovec bunch;		/* record consequent neighbour
 					   iovecs to punch together */
diff --git a/criu/pagemap.c b/criu/pagemap.c
index 08e3945..7babca3 100644
--- a/criu/pagemap.c
+++ b/criu/pagemap.c
@@ -68,7 +68,6 @@ static int punch_hole(struct page_read *pr, unsigned long off,
 int dedup_one_iovec(struct page_read *pr, struct iovec *iov)
 {
 	unsigned long off;
-	unsigned long off_real;
 	unsigned long iov_end;
 
 	iov_end = (unsigned long)iov->iov_base + iov->iov_len;
@@ -95,9 +94,8 @@ int dedup_one_iovec(struct page_read *pr, struct iovec *iov)
 			return -1;
 		pagemap2iovec(pr->pe, &piov);
 		piov_end = (unsigned long)piov.iov_base + piov.iov_len;
-		off_real = lseek(img_raw_fd(pr->pi), 0, SEEK_CUR);
 		if (!pr->pe->in_parent) {
-			ret = punch_hole(pr, off_real, min(piov_end, iov_end) - off, false);
+			ret = punch_hole(pr, pr->pi_off, min(piov_end, iov_end) - off, false);
 			if (ret == -1)
 				return ret;
 		}
@@ -156,7 +154,7 @@ static void skip_pagemap_pages(struct page_read *pr, unsigned long len)
 
 	pr_debug("\tpr%u Skip %lu bytes from page-dump\n", pr->id, len);
 	if (!pr->pe->in_parent)
-		lseek(img_raw_fd(pr->pi), len, SEEK_CUR);
+		pr->pi_off += len;
 	pr->cvaddr += len;
 }
 
@@ -259,7 +257,7 @@ static int read_pagemap_page(struct page_read *pr, unsigned long vaddr, int nr,
 		} while (nr);
 	} else {
 		int fd = img_raw_fd(pr->pi);
-		off_t current_vaddr = lseek(fd, 0, SEEK_CUR);
+		off_t current_vaddr = lseek(fd, pr->pi_off, SEEK_SET);
 
 		pr_debug("\tpr%u Read page from self %lx/%"PRIx64"\n", pr->id, pr->cvaddr, current_vaddr);
 		ret = read(fd, buf, len);
@@ -268,6 +266,8 @@ static int read_pagemap_page(struct page_read *pr, unsigned long vaddr, int nr,
 			return -1;
 		}
 
+		pr->pi_off += len;
+
 		if (opts.auto_dedup) {
 			ret = punch_hole(pr, current_vaddr, len, false);
 			if (ret == -1) {
@@ -431,6 +431,8 @@ int open_page_read_at(int dfd, int pid, struct page_read *pr, int pr_flags)
 
 	pr->pe = NULL;
 	pr->parent = NULL;
+	pr->cvaddr = 0;
+	pr->pi_off = 0;
 	pr->bunch.iov_len = 0;
 	pr->bunch.iov_base = NULL;
 
-- 
1.9.1