ecryptfs: move ecryptfs_xattr_handlers to .rodata

This makes it harder for accidental or malicious changes to
ecryptfs_xattr_handlers at runtime.

Cc: Tyler Hicks <[e-mail]>
Cc: [e-mail]
Signed-off-by: Wedson Almeida Filho <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Christian Brauner <[e-mail]>

fs/ecryptfs/ecryptfs_kernel.h

···
 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
 		       loff_t offset);
 
-extern const struct xattr_handler *ecryptfs_xattr_handlers[];
+extern const struct xattr_handler * const ecryptfs_xattr_handlers[];
 
 #endif /* #ifndef ECRYPTFS_KERNEL_H */

fs/ecryptfs/inode.c

···
 	.set = ecryptfs_xattr_set,
 };
 
-const struct xattr_handler *ecryptfs_xattr_handlers[] = {
+const struct xattr_handler * const ecryptfs_xattr_handlers[] = {
 	&ecryptfs_xattr_handler,
 	NULL
 };