tools/vm/page-types.c: make walk_file() aware of address range option

Patch series "tools/vm/page-types.c: a few improvements".

This patchset adds some improvements on tools/vm/page-types.c.  Patch
1/3 makes -a option (specify address range) work with -f (file cache
mode).  Patch 2/3 and 3/3 are to fix minor formatting issues of this
tool.  These would make life a little easier for the users of this tool.

Please see individual patches for more details about specific issues.

This patch (of 3):

-a|--addr option is used to limit the range of address to be scanned for
page status.  It works now for physical address space (dafult mode) or for
virtual address space (with -p option), but not for file address space
(with -f option).  So make walk_file() aware of -a option.

Link: https://lkml.kernel.org/r/20211004061325.1525902-1-naoya.horiguchi@linux.dev
Link: https://lkml.kernel.org/r/20211004061325.1525902-2-naoya.horiguchi@linux.devSigned-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Christian Hansen <chansen3@cisco.com>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Bin Wang <wangbin224@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/vm/page-types.c

@@ -967,22 +967,19 @@ static struct sigaction sigbus_action = {
 	.sa_flags = SA_SIGINFO,
 };
 
-static void walk_file(const char *name, const struct stat *st)
+static void walk_file_range(const char *name, int fd,
+			    unsigned long off, unsigned long end)
 {
 	uint8_t vec[PAGEMAP_BATCH];
 	uint64_t buf[PAGEMAP_BATCH], flags;
 	uint64_t cgroup = 0;
 	uint64_t mapcnt = 0;
 	unsigned long nr_pages, pfn, i;
-	off_t off, end = st->st_size;
-	int fd;
 	ssize_t len;
 	void *ptr;
 	int first = 1;
 
-	fd = checked_open(name, O_RDONLY|O_NOATIME|O_NOFOLLOW);
-
-	for (off = 0; off < end; off += len) {
+	for (; off < end; off += len) {
 		nr_pages = (end - off + page_size - 1) / page_size;
 		if (nr_pages > PAGEMAP_BATCH)
 			nr_pages = PAGEMAP_BATCH;
@@ -1043,6 +1040,21 @@ static void walk_file(const char *name, const struct stat *st)
 				 flags, cgroup, mapcnt, buf[i]);
 		}
 	}
+}
+
+static void walk_file(const char *name, const struct stat *st)
+{
+	int i;
+	int fd;
+
+	fd = checked_open(name, O_RDONLY|O_NOATIME|O_NOFOLLOW);
+
+	if (!nr_addr_ranges)
+		add_addr_range(0, st->st_size / page_size);
+
+	for (i = 0; i < nr_addr_ranges; i++)
+		walk_file_range(name, fd, opt_offset[i] * page_size,
+				(opt_offset[i] + opt_size[i]) * page_size);
 
 	close(fd);
 }