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: Daniel Jordan <[email protected]>
Acked-by: Steffen Klassert <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: [email protected]
Cc: [email protected]
---
crypto/pcrypt.c | 4 ----
kernel/padata.c | 17 +++++++++--------
2 files changed, 9 insertions(+), 12 deletions(-)
diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c
index 2ec36e6a132f..543792e0ebf0 100644
--- a/crypto/pcrypt.c
+++ b/crypto/pcrypt.c
@@ -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;
}
diff --git a/kernel/padata.c b/kernel/padata.c
index 863053a1e379..29d44edd6733 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -907,8 +907,6 @@ 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,
@@ -926,11 +924,13 @@ 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))
@@ -956,12 +956,16 @@ static struct padata_instance *padata_alloc(const char *name,
cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD,
&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);
@@ -975,12 +979,9 @@ 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);
--
2.23.0