From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S970128AbdDTLXL (ORCPT ); Thu, 20 Apr 2017 07:23:11 -0400 Received: from terminus.zytor.com ([65.50.211.136]:33631 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965927AbdDTLXB (ORCPT ); Thu, 20 Apr 2017 07:23:01 -0400 Date: Thu, 20 Apr 2017 04:20:23 -0700 From: tip-bot for Sebastian Andrzej Siewior Message-ID: Cc: steffen.klassert@secunet.com, bigeasy@linutronix.de, rostedt@goodmis.org, hpa@zytor.com, tglx@linutronix.de, peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org Reply-To: hpa@zytor.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, rostedt@goodmis.org, bigeasy@linutronix.de, steffen.klassert@secunet.com In-Reply-To: <20170418170552.697398655@linutronix.de> References: <20170418170552.697398655@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:smp/hotplug] padata: Avoid nested calls to get_online_cpus() in pcrypt_init_padata() Git-Commit-ID: bbd8797975ce0191ac72d575f7e34033b5a5f620 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: bbd8797975ce0191ac72d575f7e34033b5a5f620 Gitweb: http://git.kernel.org/tip/bbd8797975ce0191ac72d575f7e34033b5a5f620 Author: Sebastian Andrzej Siewior AuthorDate: Tue, 18 Apr 2017 19:04:46 +0200 Committer: Thomas Gleixner CommitDate: Thu, 20 Apr 2017 13:08:51 +0200 padata: Avoid nested calls to get_online_cpus() in pcrypt_init_padata() pcrypt_init_padata() get_online_cpus() padata_alloc_possible() padata_alloc() get_online_cpus() The nested call to get_online_cpus() works with the current implementation, but prevents the conversion to a percpu rwsem. The other caller of padata_alloc_possible() is pcrypt_init_padata() which calls from a get_online_cpus() protected region as well. Remove the get_online_cpus() call in padata_alloc() and document the calling convention. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Steffen Klassert Cc: Peter Zijlstra Cc: Steven Rostedt Cc: linux-crypto@vger.kernel.org Link: http://lkml.kernel.org/r/20170418170552.697398655@linutronix.de --- kernel/padata.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/padata.c b/kernel/padata.c index 18992bf..e5ff511 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -945,6 +945,8 @@ static struct kobj_type padata_attr_type = { * @wq: workqueue to use for the allocated padata instance * @pcpumask: cpumask that will be used for padata parallelization * @cbcpumask: cpumask that will be used for padata serialization + * + * Must be called from a get_online_cpus() protected region */ static struct padata_instance *padata_alloc(struct workqueue_struct *wq, const struct cpumask *pcpumask, @@ -957,7 +959,6 @@ static struct padata_instance *padata_alloc(struct workqueue_struct *wq, if (!pinst) goto err; - get_online_cpus(); if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL)) goto err_free_inst; if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) { @@ -997,7 +998,6 @@ err_free_masks: free_cpumask_var(pinst->cpumask.cbcpu); err_free_inst: kfree(pinst); - put_online_cpus(); err: return NULL; } @@ -1008,6 +1008,8 @@ err: * parallel workers. * * @wq: workqueue to use for the allocated padata instance + * + * Must be called from a get_online_cpus() protected region */ struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq) {