sysctl: drop sysctl_is_perm_empty_ctl_table

It is used only twice and those callers are simpler with
sysctl_is_perm_empty_ctl_header().
So use this sibling function.

This is part of an effort to constify definition of struct ctl_table.
For this effort the mutable member 'type' is moved from
struct ctl_table to struct ctl_table_header.
Unifying the macros sysctl_is_perm_empty_ctl_* makes this easier.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Joel Granados <j.granados@samsung.com>

Author: t-8ch

fs/proc/proc_sysctl.c

@@ -48,10 +48,8 @@ struct ctl_table_header *register_sysctl_mount_point(const char *path)
 }
 EXPORT_SYMBOL(register_sysctl_mount_point);
 
-#define sysctl_is_perm_empty_ctl_table(tptr)		\
-	(tptr[0].type == SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY)
 #define sysctl_is_perm_empty_ctl_header(hptr)		\
-	(sysctl_is_perm_empty_ctl_table(hptr->ctl_table))
+	(hptr->ctl_table[0].type == SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY)
 #define sysctl_set_perm_empty_ctl_header(hptr)		\
 	(hptr->ctl_table[0].type = SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY)
 #define sysctl_clear_perm_empty_ctl_header(hptr)	\
@@ -233,7 +231,7 @@ static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
 
 	/* Am I creating a permanently empty directory? */
 	if (header->ctl_table_size > 0 &&
-	    sysctl_is_perm_empty_ctl_table(header->ctl_table)) {
+	    sysctl_is_perm_empty_ctl_header(header)) {
 		if (!RB_EMPTY_ROOT(&dir->root))
 			return -EINVAL;
 		sysctl_set_perm_empty_ctl_header(dir_h);
@@ -1204,7 +1202,7 @@ static bool get_links(struct ctl_dir *dir,
 	struct ctl_table *entry, *link;
 
 	if (header->ctl_table_size == 0 ||
-	    sysctl_is_perm_empty_ctl_table(header->ctl_table))
+	    sysctl_is_perm_empty_ctl_header(header))
 		return true;
 
 	/* Are there links available for every entry in table? */