linux-kernel - [PATCH 2/4] padata: Flush the padata queues actively

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20100514114426.GC2184@secunet.com>
Date:	Fri, 14 May 2010 13:44:27 +0200
From:	Steffen Klassert <steffen.klassert@...unet.com>
To:	Herbert Xu <herbert@...dor.apana.org.au>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, linux-crypto@...r.kernel.org
Subject: [PATCH 2/4] padata: Flush the padata queues actively

yield was used to wait until all references of the internal control
structure in use are dropped before it is freed. This patch implements
padata_flush_queues which actively flushes the padata percpu queues
in this case.

Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 kernel/padata.c |   33 +++++++++++++++++++++++++--------
 1 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index 6d7ea48..ec6b8b7 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -417,6 +417,29 @@ static void padata_free_pd(struct parallel_data *pd)
 	kfree(pd);
 }
 
+static void padata_flush_queues(struct parallel_data *pd)
+{
+	int cpu;
+	struct padata_queue *queue;
+
+	for_each_cpu(cpu, pd->cpumask) {
+		queue = per_cpu_ptr(pd->queue, cpu);
+		flush_work(&queue->pwork);
+	}
+
+	del_timer_sync(&pd->timer);
+
+	if (atomic_read(&pd->reorder_objects))
+		padata_reorder(pd);
+
+	for_each_cpu(cpu, pd->cpumask) {
+		queue = per_cpu_ptr(pd->queue, cpu);
+		flush_work(&queue->swork);
+	}
+
+	BUG_ON(atomic_read(&pd->refcnt) != 0);
+}
+
 static void padata_replace(struct padata_instance *pinst,
 			   struct parallel_data *pd_new)
 {
@@ -428,11 +451,7 @@ static void padata_replace(struct padata_instance *pinst,
 
 	synchronize_rcu();
 
-	while (atomic_read(&pd_old->refcnt) != 0)
-		yield();
-
-	flush_workqueue(pinst->wq);
-
+	padata_flush_queues(pd_old);
 	padata_free_pd(pd_old);
 
 	pinst->flags &= ~PADATA_RESET;
@@ -695,12 +714,10 @@ void padata_free(struct padata_instance *pinst)
 
 	synchronize_rcu();
 
-	while (atomic_read(&pinst->pd->refcnt) != 0)
-		yield();
-
 #ifdef CONFIG_HOTPLUG_CPU
 	unregister_hotcpu_notifier(&pinst->cpu_notifier);
 #endif
+	padata_flush_queues(pinst->pd);
 	padata_free_pd(pinst->pd);
 	free_cpumask_var(pinst->cpumask);
 	kfree(pinst);
-- 
1.5.6.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/