[patch 03/20] padata: Make padata_alloc() static

[patch 03/20] padata: Make padata_alloc() static

[Thomas Gleixner]

[-- Attachment #1: padata--Make-padata_alloc---static.patch --]
[-- Type: text/plain, Size: 3035 bytes --]

No users outside of padata.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: linux-crypto@vger.kernel.org
---
 include/linux/padata.h |    3 ---
 kernel/padata.c        |   34 +++++++++++++++++-----------------
 2 files changed, 17 insertions(+), 20 deletions(-)

--- a/include/linux/padata.h
+++ b/include/linux/padata.h
@@ -166,9 +166,6 @@ struct padata_instance {
 
 extern struct padata_instance *padata_alloc_possible(
 					struct workqueue_struct *wq);
-extern struct padata_instance *padata_alloc(struct workqueue_struct *wq,
-					    const struct cpumask *pcpumask,
-					    const struct cpumask *cbcpumask);
 extern void padata_free(struct padata_instance *pinst);
 extern int padata_do_parallel(struct padata_instance *pinst,
 			      struct padata_priv *padata, int cb_cpu);
--- 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,
-				  const char *buf, size_t count)
+s				  const char *buf, size_t count)
 {
 	struct padata_instance *pinst;
 	struct padata_sysfs_entry *pentry;
@@ -939,19 +939,6 @@ static struct kobj_type padata_attr_type
 };
 
 /**
- * padata_alloc_possible - Allocate and initialize padata instance.
- *                         Use the cpu_possible_mask for serial and
- *                         parallel workers.
- *
- * @wq: workqueue to use for the allocated padata instance
- */
-struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
-{
-	return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
-}
-EXPORT_SYMBOL(padata_alloc_possible);
-
-/**
  * padata_alloc - allocate and initialize a padata instance and specify
  *                cpumasks for serial and parallel workers.
  *
@@ -959,9 +946,9 @@ EXPORT_SYMBOL(padata_alloc_possible);
  * @pcpumask: cpumask that will be used for padata parallelization
  * @cbcpumask: cpumask that will be used for padata serialization
  */
-struct padata_instance *padata_alloc(struct workqueue_struct *wq,
-				     const struct cpumask *pcpumask,
-				     const struct cpumask *cbcpumask)
+static struct padata_instance *padata_alloc(struct workqueue_struct *wq,
+					    const struct cpumask *pcpumask,
+					    const struct cpumask *cbcpumask)
 {
 	struct padata_instance *pinst;
 	struct parallel_data *pd = NULL;
@@ -1016,6 +1003,19 @@ struct padata_instance *padata_alloc(str
 }
 
 /**
+ * padata_alloc_possible - Allocate and initialize padata instance.
+ *                         Use the cpu_possible_mask for serial and
+ *                         parallel workers.
+ *
+ * @wq: workqueue to use for the allocated padata instance
+ */
+struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
+{
+	return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
+}
+EXPORT_SYMBOL(padata_alloc_possible);
+
+/**
  * padata_free - free a padata instance
  *
  * @padata_inst: padata instance to free

[patch 04/20] padata: Avoid nested calls to get_online_cpus() in pcrypt_init_padata()

[Thomas Gleixner]

[-- Attachment #1: kernelpadata_Avoid_get_online_cpus_recursion_via_pcrypt_init_padata.patch --]
[-- Type: text/plain, Size: 2349 bytes --]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

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 <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
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)
 {

Re: [patch 03/20] padata: Make padata_alloc() static

[Jason A. Donenfeld]

I rather like this option of padata, which, since it lives in
kernel/padata.c and linux/padata.h, should be generic and useful for
other components. Seems like the ability to allocate it for a
particular set of worker CPUs and callback CPUs could be useful down
the line. Would rather not see it become static.

Jason

Re: [patch 03/20] padata: Make padata_alloc() static

[Thomas Gleixner]

On Sun, 16 Apr 2017, Jason A. Donenfeld wrote:

> I rather like this option of padata, which, since it lives in
> kernel/padata.c and linux/padata.h, should be generic and useful for
> other components. Seems like the ability to allocate it for a
> particular set of worker CPUs and callback CPUs could be useful down
> the line. Would rather not see it become static.

It's simple enough to export it once there is an actual user. Just keeping
stuff global because it might be useful somewhere down the road is really
pointless.

Thanks,

	tglx