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Commit cc491d8e authored by Daniel Jordan's avatar Daniel Jordan Committed by Herbert Xu
Browse files

padata, pcrypt: take CPU hotplug lock internally in padata_alloc_possible 



With pcrypt's cpumask no longer used, take the CPU hotplug lock inside
padata_alloc_possible.

Useful later in the series for avoiding nested acquisition of the CPU
hotplug lock in padata when padata_alloc_possible is allocating an
unbound workqueue.

Without this patch, this nested acquisition would happen later in the
series:

      pcrypt_init_padata
        get_online_cpus
        alloc_padata_possible
          alloc_padata
            alloc_workqueue(WQ_UNBOUND)   // later in the series
              alloc_and_link_pwqs
                apply_wqattrs_lock
                  get_online_cpus         // recursive rwsem acquisition

Signed-off-by: default avatarDaniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 63d35788

crypto/pcrypt.c

+0 −4
Original line number Diff line number Diff line
@@ -308,8 +308,6 @@ static int pcrypt_init_padata(struct padata_instance **pinst, const char *name) 
{

	int ret = -ENOMEM;



	get_online_cpus();



	*pinst = padata_alloc_possible(name);

	if (!*pinst)

		return ret;
@@ -318,8 +316,6 @@ static int pcrypt_init_padata(struct padata_instance **pinst, const char *name) 
	if (ret)

		padata_free(*pinst);



	put_online_cpus();



	return ret;

}

kernel/padata.c

+9 −8
Original line number Diff line number Diff line
@@ -955,8 +955,6 @@ static struct kobj_type padata_attr_type = { 
 * @name: used to identify the 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(const char *name,

					    const struct cpumask *pcpumask,
@@ -974,11 +972,13 @@ static struct padata_instance *padata_alloc(const char *name, 
	if (!pinst->wq)

		goto err_free_inst;



	get_online_cpus();



	if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))

		goto err_free_wq;

		goto err_put_cpus;

	if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {

		free_cpumask_var(pinst->cpumask.pcpu);

		goto err_free_wq;

		goto err_put_cpus;

	}

	if (!padata_validate_cpumask(pinst, pcpumask) ||

	    !padata_validate_cpumask(pinst, cbcpumask))
@@ -1002,12 +1002,16 @@ static struct padata_instance *padata_alloc(const char *name, 
#ifdef CONFIG_HOTPLUG_CPU

	cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);

#endif



	put_online_cpus();



	return pinst;



err_free_masks:

	free_cpumask_var(pinst->cpumask.pcpu);

	free_cpumask_var(pinst->cpumask.cbcpu);

err_free_wq:

err_put_cpus:

	put_online_cpus();

	destroy_workqueue(pinst->wq);

err_free_inst:

	kfree(pinst);
@@ -1021,12 +1025,9 @@ static struct padata_instance *padata_alloc(const char *name, 
 *                         parallel workers.

 *

 * @name: used to identify the instance

 *

 * Must be called from a cpus_read_lock() protected region

 */

struct padata_instance *padata_alloc_possible(const char *name)

{

	lockdep_assert_cpus_held();

	return padata_alloc(name, cpu_possible_mask, cpu_possible_mask);

}

EXPORT_SYMBOL(padata_alloc_possible);