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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2017-05-24 10:15:18 +0200
committerThomas Gleixner <tglx@linutronix.de>2017-05-26 10:10:37 +0200
commitc5a81c8ff816d89941fe86961b286765d6ca2f5f (patch)
treee0b18776387a4f5759065ea2bfa271ea521a90bd /kernel/padata.c
parent9596695ee1e7eedd743c43811fe68299eb005b5c (diff)
downloadlinux-c5a81c8ff816d89941fe86961b286765d6ca2f5f.tar.bz2
padata: Avoid nested calls to cpus_read_lock() in pcrypt_init_padata()
pcrypt_init_padata() cpus_read_lock() padata_alloc_possible() padata_alloc() cpus_read_lock() The nested call to cpus_read_lock() 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 cpus_read_lock() protected region as well. Remove the cpus_read_lock() call in padata_alloc() and document the calling convention. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-crypto@vger.kernel.org Link: http://lkml.kernel.org/r/20170524081547.571278910@linutronix.de
Diffstat (limited to 'kernel/padata.c')
-rw-r--r--kernel/padata.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/kernel/padata.c b/kernel/padata.c
index 0c708f648853..868f947166d7 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -940,6 +940,8 @@ 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 cpus_read_lock() protected region
*/
static struct padata_instance *padata_alloc(struct workqueue_struct *wq,
const struct cpumask *pcpumask,
@@ -952,7 +954,6 @@ 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)) {
@@ -976,14 +977,12 @@ static struct padata_instance *padata_alloc(struct workqueue_struct *wq,
pinst->flags = 0;
- put_online_cpus();
-
BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
kobject_init(&pinst->kobj, &padata_attr_type);
mutex_init(&pinst->lock);
#ifdef CONFIG_HOTPLUG_CPU
- cpuhp_state_add_instance_nocalls(hp_online, &pinst->node);
+ cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);
#endif
return pinst;
@@ -992,7 +991,6 @@ err_free_masks:
free_cpumask_var(pinst->cpumask.cbcpu);
err_free_inst:
kfree(pinst);
- put_online_cpus();
err:
return NULL;
}
@@ -1003,9 +1001,12 @@ err:
* parallel workers.
*
* @wq: workqueue to use for the allocated padata instance
+ *
+ * Must be called from a cpus_read_lock() protected region
*/
struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
{
+ lockdep_assert_cpus_held();
return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
}
EXPORT_SYMBOL(padata_alloc_possible);