ext4: constify static data that is never modified

Constify static data in ext4 that is never (intentionally) modified so
that it is placed in .rodata and benefits from memory protection.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 42145be..d74dc5f 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -34,7 +34,7 @@
 	ptr_ext4_super_block_offset,
 } attr_ptr_t;
 
-static const char *proc_dirname = "fs/ext4";
+static const char proc_dirname[] = "fs/ext4";
 static struct proc_dir_entry *ext4_proc_root;
 
 struct ext4_attr {
@@ -375,7 +375,7 @@
 PROC_FILE_SHOW_DEFN(es_shrinker_info);
 PROC_FILE_SHOW_DEFN(options);
 
-static struct ext4_proc_files {
+static const struct ext4_proc_files {
 	const char *name;
 	const struct file_operations *fops;
 } proc_files[] = {
@@ -388,7 +388,7 @@
 int ext4_register_sysfs(struct super_block *sb)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
-	struct ext4_proc_files *p;
+	const struct ext4_proc_files *p;
 	int err;
 
 	sbi->s_kobj.kset = &ext4_kset;
@@ -412,7 +412,7 @@
 void ext4_unregister_sysfs(struct super_block *sb)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
-	struct ext4_proc_files *p;
+	const struct ext4_proc_files *p;
 
 	if (sbi->s_proc) {
 		for (p = proc_files; p->name; p++)