smb: move cifs_xattr_handlers to .rodata

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

Cc: Steve French <sfrench@samba.org>
Cc: Paulo Alcantara <pc@manguebit.com>
Cc: Ronnie Sahlberg <lsahlber@redhat.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230930050033.41174-24-wedsonaf@gmail.com
Reviewed-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/smb/client/cifsfs.h

@@ -127,7 +127,7 @@ extern int cifs_symlink(struct mnt_idmap *idmap, struct inode *inode,
 			struct dentry *direntry, const char *symname);
 
 #ifdef CONFIG_CIFS_XATTR
-extern const struct xattr_handler *cifs_xattr_handlers[];
+extern const struct xattr_handler * const cifs_xattr_handlers[];
 extern ssize_t	cifs_listxattr(struct dentry *, char *, size_t);
 #else
 # define cifs_xattr_handlers NULL

fs/smb/client/xattr.c

@@ -478,7 +478,7 @@ static const struct xattr_handler smb3_ntsd_full_xattr_handler = {
 	.set = cifs_xattr_set,
 };
 
-const struct xattr_handler *cifs_xattr_handlers[] = {
+const struct xattr_handler * const cifs_xattr_handlers[] = {
 	&cifs_user_xattr_handler,
 	&cifs_os2_xattr_handler,
 	&cifs_cifs_acl_xattr_handler,