From: Sebastian Andrzej Siewior 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: linux-crypto@vger.kernel.org --- kernel/padata.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/kernel/padata.c +++ b/kernel/padata.c @@ -913,7 +913,7 @@ static ssize_t padata_sysfs_show(struct } static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr, -s const char *buf, size_t count) + const char *buf, size_t count) { struct padata_instance *pinst; struct padata_sysfs_entry *pentry; @@ -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_al 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 @@ static struct padata_instance *padata_al free_cpumask_var(pinst->cpumask.cbcpu); err_free_inst: kfree(pinst); - put_online_cpus(); err: return NULL; } @@ -1008,6 +1008,8 @@ static struct padata_instance *padata_al * 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) {