tools/vm/page-types.c: move show_file() to summary output

Currently file info from show_file() is printed out within page list
like below, but this is inconvenient a little to utilize the page list
from other scripts (maybe needs additional filtering).

    $ ./page-types -f page-types.c -l
    foffset offset  len     flags
    page-types.c Inode: 15108680 Size: 30953 (8 pages)
    Modify: Sat Oct  2 23:11:20 2021 (2399 seconds ago)
    Access: Sat Oct  2 23:11:28 2021 (2391 seconds ago)
    0       d9f59e  1       ___U_lA____________________________________
    1       1031eb5 1       __RU_l_____________________________________
    2       13bf717 1       __RU_l_____________________________________
    3       13ac333 1       ___U_lA____________________________________
    4       d9f59f  1       __RU_l_____________________________________
    5       183fd49 1       ___U_lA____________________________________
    6       13cbf69 1       ___U_lA____________________________________
    7       d9ef05  1       ___U_lA____________________________________

                 flags      page-count       MB  symbolic-flags                     long-symbolic-flags
    0x000000000000002c               3        0  __RU_l_____________________________________        referenced,uptodate,lru
    0x0000000000000068               5        0  ___U_lA____________________________________        uptodate,lru,active
                 total               8        0

With this patch file info is printed out in summary part like below:

    $ ./page-types -f page-types.c -l
    foffset offset  len     flags
    0       d9f59e  1       ___U_lA_____________________________________
    1       1031eb5 1       __RU_l______________________________________
    2       13bf717 1       __RU_l______________________________________
    3       13ac333 1       ___U_lA_____________________________________
    4       d9f59f  1       __RU_l______________________________________
    5       183fd49 1       ___U_lA_____________________________________
    6       13cbf69 1       ___U_lA_____________________________________

    page-types.c Inode: 15108680 Size: 30953 (8 pages)
    Modify: Sat Oct  2 23:11:20 2021 (2435 seconds ago)
    Access: Sat Oct  2 23:11:28 2021 (2427 seconds ago)

                 flags      page-count       MB  symbolic-flags                     long-symbolic-flags
    0x000000000000002c               3        0  __RU_l______________________________________       referenced,uptodate,lru
    0x0000000000000068               4        0  ___U_lA_____________________________________       uptodate,lru,active
                 total               7        0

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Naoya Horiguchi <[email protected]>
Cc: Bin Wang <[email protected]>
Cc: Changbin Du <[email protected]>
Cc: Christian Hansen <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

tools/vm/page-types.c

@@ -1034,7 +1034,6 @@ static void walk_file_range(const char *name, int fd,
 			if (first && opt_list) {
 				first = 0;
 				flush_page_range();
-				show_file(name, st);
 			}
 			add_page(off / page_size + i, pfn,
 				 flags, cgroup, mapcnt, buf[i]);
@@ -1074,10 +1073,10 @@ int walk_tree(const char *name, const struct stat *st, int type, struct FTW *f)
 	return 0;
 }
 
+struct stat st;
+
 static void walk_page_cache(void)
 {
-	struct stat st;
-
 	kpageflags_fd = checked_open(opt_kpageflags, O_RDONLY);
 	pagemap_fd = checked_open("/proc/self/pagemap", O_RDONLY);
 	sigaction(SIGBUS, &sigbus_action, NULL);
@@ -1374,6 +1373,11 @@ int main(int argc, char *argv[])
 	if (opt_list)
 		printf("\n\n");
 
+	if (opt_file) {
+		show_file(opt_file, &st);
+		printf("\n");
+	}
+
 	show_summary();
 
 	if (opt_list_mapcnt)