[LTP] [PATCH v2] syscalls/keyctl02: wait for last key to be garbage collected

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
>  static void do_test(void)
>  {
> -	int i;
> -	key_serial_t key;
> +	int i, ret;
> +	key_serial_t key, key_inv;
>  	pthread_t pth[4];
>  
>  	for (i = 0; i < LOOPS; i++) {
> @@ -94,13 +95,45 @@ static void do_test(void)
>  		SAFE_PTHREAD_JOIN(pth[3], NULL);
>  	}
>  
> +	/*
> +	 * Kernel should start garbage collect when last reference to key
> +	 * is removed (see key_put()). Since we are adding keys with identical
> +	 * description and type, each replacement should schedule a gc run,
> +	 * see comment at __key_link().
> +	 *
> +	 * We create extra key here, to remove reference to last revoked key.
> +	 */
> +	key_inv = add_key("user", "ltptestkey", "foo", 3,
> +		KEY_SPEC_PROCESS_KEYRING);
> +	if (key_inv == -1)
> +		tst_brk(TBROK | TERRNO, "Failed to add key");
> +
> +	/*
> +	 * If we have invalidate, we can drop extra key immediately as well,
> +	 * which also schedules gc.
> +	 */
> +	if (keyctl(KEYCTL_INVALIDATE, key_inv) == -1 && errno != EOPNOTSUPP)
> +		tst_brk(TBROK | TERRNO, "Failed to invalidate key");
> +
> +	/*
> +	 * At this point we are quite confident that gc has been scheduled,
> +	 * so we wait and periodically check for last test key to be removed.
> +	 */
> +	for (i = 0; i < MAX_WAIT_FOR_GC_MS; i += 100) {
> +		ret = keyctl(KEYCTL_REVOKE, key);
> +		if (ret == -1 && errno == ENOKEY)
> +			break;
> +		usleep(100*1000);
> +	}
> +
> +	tst_res(TINFO, "waiting for key gc took: %d ms", i);

Minor enhancement may be:

	if (i)
		tst_res(TINFO, "waiting for key gc took: %d ms", i);


Anyways, the patch looks good, acked.

-- 
Cyril Hrubis
chrubis@suse.cz