Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754711AbaLWFk0 (ORCPT ); Tue, 23 Dec 2014 00:40:26 -0500 Received: from helcar.apana.org.au ([209.40.204.226]:37675 "EHLO helcar.apana.org.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751276AbaLWFkZ (ORCPT ); Tue, 23 Dec 2014 00:40:25 -0500 Subject: [PATCH 1/5] hwrng: core - Use struct completion for cleanup_done 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 16:40:17 +1100 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There is no point in doing a manual completion for cleanup_done when struct completion fits in perfectly. Signed-off-by: Herbert Xu --- drivers/char/hw_random/core.c | 12 +++--------- include/linux/hw_random.h | 3 ++- 2 files changed, 5 insertions(+), 10 deletions(-) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 6ec4225..3dba2cf 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -60,7 +60,6 @@ static DEFINE_MUTEX(rng_mutex); static DEFINE_MUTEX(reading_mutex); static int data_avail; static u8 *rng_buffer, *rng_fillbuf; -static DECLARE_WAIT_QUEUE_HEAD(rng_done); static unsigned short current_quality; static unsigned short default_quality; /* = 0; default to "off" */ @@ -100,10 +99,7 @@ static inline void cleanup_rng(struct kref *kref) if (rng->cleanup) rng->cleanup(rng); - /* cleanup_done should be updated after cleanup finishes */ - smp_wmb(); - rng->cleanup_done = true; - wake_up_all(&rng_done); + complete(&rng->cleanup_done); } static void set_current_rng(struct hwrng *rng) @@ -498,7 +494,7 @@ int hwrng_register(struct hwrng *rng) add_early_randomness(rng); } - rng->cleanup_done = false; + init_completion(&rng->cleanup_done); out_unlock: mutex_unlock(&rng_mutex); @@ -532,9 +528,7 @@ void hwrng_unregister(struct hwrng *rng) } else mutex_unlock(&rng_mutex); - /* Just in case rng is reading right now, wait. */ - wait_event(rng_done, rng->cleanup_done && - atomic_read(&rng->ref.refcount) == 0); + wait_for_completion(&rng->cleanup_done); } EXPORT_SYMBOL_GPL(hwrng_unregister); diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h index 7832e50..eb7b414 100644 --- a/include/linux/hw_random.h +++ b/include/linux/hw_random.h @@ -12,6 +12,7 @@ #ifndef LINUX_HWRANDOM_H_ #define LINUX_HWRANDOM_H_ +#include #include #include #include @@ -46,7 +47,7 @@ struct hwrng { /* internal. */ struct list_head list; struct kref ref; - bool cleanup_done; + struct completion cleanup_done; }; /** Register a new Hardware Random Number Generator driver. */ -- 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/