Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754750AbaLWFka (ORCPT ); Tue, 23 Dec 2014 00:40:30 -0500 Received: from helcar.apana.org.au ([209.40.204.226]:53278 "EHLO helcar.apana.org.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754697AbaLWFk1 (ORCPT ); Tue, 23 Dec 2014 00:40:27 -0500 Subject: [PATCH 3/5] hwrng: core - Do not register device opportunistically References: <20141223053909.GA28001@gondor.apana.org.au> To: Fengguang Wu , Rusty Russell , LKP , linux-kernel@vger.kernel.org, Linux Crypto Mailing List , Amos Kong , m@bues.ch, mpm@selenic.com, amit.shah@redhat.com Message-Id: From: Herbert Xu Date: Tue, 23 Dec 2014 16:40:19 +1100 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently we only register the device when a valid RNG is added. However the way it's done is buggy because we test whether there is a current RNG to determine whether we need to register. As the current RNG may be missing due to a reinitialisation error this can lead to a reregistration of the device. As the device already has to handle a NULL current RNG anyway, let's just register the device always and remove the complexity. Signed-off-by: Herbert Xu --- drivers/char/hw_random/core.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 42827fd..1d342f0 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -372,14 +372,14 @@ static DEVICE_ATTR(rng_available, S_IRUGO, NULL); -static void unregister_miscdev(void) +static void __exit unregister_miscdev(void) { device_remove_file(rng_miscdev.this_device, &dev_attr_rng_available); device_remove_file(rng_miscdev.this_device, &dev_attr_rng_current); misc_deregister(&rng_miscdev); } -static int register_miscdev(void) +static int __init register_miscdev(void) { int err; @@ -484,12 +484,6 @@ int hwrng_register(struct hwrng *rng) if (err) goto out_unlock; set_current_rng(rng); - - err = register_miscdev(); - if (err) { - drop_current_rng(); - goto out_unlock; - } } list_add_tail(&rng->list, &rng_list); @@ -530,7 +524,6 @@ void hwrng_unregister(struct hwrng *rng) if (list_empty(&rng_list)) { mutex_unlock(&rng_mutex); - unregister_miscdev(); if (hwrng_fill) kthread_stop(hwrng_fill); } else @@ -540,16 +533,24 @@ void hwrng_unregister(struct hwrng *rng) } EXPORT_SYMBOL_GPL(hwrng_unregister); -static void __exit hwrng_exit(void) +static int __init hwrng_modinit(void) +{ + return register_miscdev(); +} + +static void __exit hwrng_modexit(void) { mutex_lock(&rng_mutex); BUG_ON(current_rng); kfree(rng_buffer); kfree(rng_fillbuf); mutex_unlock(&rng_mutex); + + unregister_miscdev(); } -module_exit(hwrng_exit); +module_init(hwrng_modinit); +module_exit(hwrng_modexit); MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver"); MODULE_LICENSE("GPL"); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/