mem: Remove zero page from the end of mem image files

This was required when pages were stored in elf files for
exec. Now we can stop reading it on eof.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -1466,10 +1466,6 @@ static int cr_dump_shmem(void)
 		if (pfn != nrpages)
 			goto err_close;
 
-		err = write_img(fd, &zero_page_entry);
-		if (err < 0)
-			goto err_close;
-
 		close(fd);
 		munmap(addr,  si->size);
 		xfree(map);

cr-restore.c

@@ -472,11 +472,8 @@ static int restore_shmem_content(void *addr, struct shmem_info *si)
 	}
 
 	while (1) {
-		ret = read_img_buf(fd, &offset, sizeof(offset));
-		if (ret < 0)
-			break;
-
-		if (final_page_va(offset))
+		ret = read_img_buf_eof(fd, &offset, sizeof(offset));
+		if (ret <= 0)
 			break;
 
 		if (offset + PAGE_SIZE > si->size)

cr-show.c

@@ -202,9 +202,7 @@ void show_pages(int fd_pages, struct cr_options *o)
 		while (1) {
 			struct page_entry e;
 
-			if (read_img(fd_pages, &e) < 0)
-				break;
-			if (final_page_entry(&e))
+			if (read_img_eof(fd_pages, &e) <= 0)
 				break;
 
 			print_data(e.va, e.data, PAGE_IMAGE_SIZE);
@@ -217,12 +215,11 @@ void show_pages(int fd_pages, struct cr_options *o)
 
 			pr_msg("\t");
 			for (i = 0; i < DEF_PAGES_PER_LINE; i++) {
-				if (read_img(fd_pages, &e) < 0)
-					goto out;
-				if (final_page_entry(&e)) {
+				if (read_img_eof(fd_pages, &e) <= 0) {
 					pr_msg("\n");
 					goto out;
 				}
+
 				pr_msg("%16lx ", e.va);
 			}
 			pr_msg("\n");

crtools.c

@@ -24,7 +24,6 @@
 #include "ipc_ns.h"
 
 static struct cr_options opts;
-struct page_entry zero_page_entry = {.va = ~0LL};
 
 /*
  * The cr fd set is the set of files where the information

include/crtools.h

@@ -8,7 +8,6 @@
 #include "util.h"
 #include "image.h"
 
-extern struct page_entry zero_page_entry;
 extern void free_pstree(struct list_head *pstree_list);
 
 #define CR_FD_PERM		(S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH)

include/image.h

@@ -195,9 +195,6 @@ struct page_entry {
 	u8	data[PAGE_IMAGE_SIZE];
 } __packed;
 
-#define final_page_va(va)		((va) == ~0LL)
-#define final_page_entry(page_entry)	(final_page_va((page_entry)->va))
-
 struct sa_entry {
 	u64		sigaction;
 	u64		flags;

parasite-syscall.c

@@ -536,9 +536,6 @@ int parasite_dump_pages_seized(struct parasite_ctl *ctl, struct list_head *vma_a
 
 	parasite_execute(PARASITE_CMD_DUMPPAGES_FINI, ctl, NULL, 0);
 
-	if (write_img(fdset_fd(cr_fdset, CR_FD_PAGES), &zero_page_entry))
-		goto out;
-
 	pr_info("\n");
 	pr_info("Summary: %16li pages dumped\n", nrpages_dumped);
 	ret = 0;

restorer.c

@@ -370,13 +370,12 @@ long restore_task(struct task_restore_core_args *args)
 		ret = sys_read(args->fd_pages, &va, sizeof(va));
 		if (!ret)
 			break;
+
 		if (ret != sizeof(va)) {
 			write_num_n(__LINE__);
 			write_num_n(ret);
 			goto core_restore_end;
 		}
-		if (final_page_va(va))
-			break;
 
 		ret = sys_read(args->fd_pages, (void *)va, PAGE_SIZE);
 		if (ret != PAGE_SIZE) {