Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752605AbaBHQTZ (ORCPT ); Sat, 8 Feb 2014 11:19:25 -0500 Received: from mail-wi0-f178.google.com ([209.85.212.178]:58244 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752507AbaBHQTC (ORCPT ); Sat, 8 Feb 2014 11:19:02 -0500 From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Andrew Morton , Christoph Hellwig , Ingo Molnar , Jan Kara , Jens Axboe Subject: [PATCH 11/11] smp: Enhance and precise the role & requirements of __smp_call_function_single() Date: Sat, 8 Feb 2014 17:18:40 +0100 Message-Id: <1391876320-25068-12-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1391876320-25068-1-git-send-email-fweisbec@gmail.com> References: <1391876320-25068-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Be more specific on the description of __smp_call_function_single(). It's actually not that much about just being able to embed a csd in an object. Cc: Andrew Morton Cc: Christoph Hellwig Cc: Ingo Molnar Cc: Jan Kara Cc: Jens Axboe Signed-off-by: Frederic Weisbecker --- kernel/smp.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/kernel/smp.c b/kernel/smp.c index b767631..24cb936 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -238,13 +238,20 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info, EXPORT_SYMBOL(smp_call_function_single); /** - * __smp_call_function_single(): Run a function on a specific CPU + * __smp_call_function_single(): Run an asynchronous function on a + * specific CPU. * @cpu: The CPU to run on. * @csd: Pre-allocated and setup data structure * - * Like smp_call_function_single(), but allow caller to pass in a - * pre-allocated data structure. Useful for embedding @data inside - * other structures, for instance. + * Like smp_call_function_single(), but the call is asynchonous and + * can thus be done from contexts with disabled interrupts. + * + * The caller passes his own pre-allocated data structure + * (ie: embedded in an object) and is responsible for synchronizing it + * such that the IPIs performed on the @csd are strictly serialized. + * + * NOTE: Be careful, there is unfortunately no current debugging facility to + * validate the correctness of this serialization. */ int __smp_call_function_single(int cpu, struct call_single_data *csd) { -- 1.8.3.1 -- 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/