drivers/gpu/drm/amd/amdkfd/kfd_process.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright 2014 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  */

 #include <linux/mutex.h>
 #include <linux/log2.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/amd-iommu.h>
 #include <linux/notifier.h>
 struct mm_struct;

 #include "kfd_priv.h"

 /*
  * Initial size for the array of queues.
  * The allocated size is doubled each time
  * it is exceeded up to MAX_PROCESS_QUEUES.
  */
 #define INITIAL_QUEUE_ARRAY_SIZE 16

 /*
  * List of struct kfd_process (field kfd_process).
  * Unique/indexed by mm_struct*
  */
 #define KFD_PROCESS_TABLE_SIZE 5 /* bits: 32 entries */
 static DEFINE_HASHTABLE(kfd_processes_table, KFD_PROCESS_TABLE_SIZE);
 static DEFINE_MUTEX(kfd_processes_mutex);

 DEFINE_STATIC_SRCU(kfd_processes_srcu);

 static struct workqueue_struct *kfd_process_wq;

 struct kfd_process_release_work {
 	struct work_struct kfd_work;
 	struct kfd_process *p;
 };

 static struct kfd_process *find_process(const struct task_struct *thread);
 static struct kfd_process *create_process(const struct task_struct *thread);

 void kfd_process_create_wq(void)
 {
 	if (!kfd_process_wq)
 		kfd_process_wq = create_workqueue("kfd_process_wq");
 }

 void kfd_process_destroy_wq(void)
 {
 	if (kfd_process_wq) {
 		flush_workqueue(kfd_process_wq);
 		destroy_workqueue(kfd_process_wq);
 		kfd_process_wq = NULL;
 	}
 }

 struct kfd_process *kfd_create_process(const struct task_struct *thread)
 {
 	struct kfd_process *process;

 	BUG_ON(!kfd_process_wq);

 	if (thread->mm == NULL)
 		return ERR_PTR(-EINVAL);

 	/* Only the pthreads threading model is supported. */
 	if (thread->group_leader->mm != thread->mm)
 		return ERR_PTR(-EINVAL);

 	/* Take mmap_sem because we call __mmu_notifier_register inside */
 	down_write(&thread->mm->mmap_sem);

 	/*
 	 * take kfd processes mutex before starting of process creation
 	 * so there won't be a case where two threads of the same process
 	 * create two kfd_process structures
 	 */
 	mutex_lock(&kfd_processes_mutex);

 	/* A prior open of /dev/kfd could have already created the process. */
 	process = find_process(thread);
 	if (process)
 		pr_debug("kfd: process already found\n");

 	if (!process)
 		process = create_process(thread);

 	mutex_unlock(&kfd_processes_mutex);

 	up_write(&thread->mm->mmap_sem);

 	return process;
 }

 struct kfd_process *kfd_get_process(const struct task_struct *thread)
 {
 	struct kfd_process *process;

 	if (thread->mm == NULL)
 		return ERR_PTR(-EINVAL);

 	/* Only the pthreads threading model is supported. */
 	if (thread->group_leader->mm != thread->mm)
 		return ERR_PTR(-EINVAL);

 	process = find_process(thread);

 	return process;
 }

 static struct kfd_process *find_process_by_mm(const struct mm_struct *mm)
 {
 	struct kfd_process *process;

 	hash_for_each_possible_rcu(kfd_processes_table, process,
 					kfd_processes, (uintptr_t)mm)
 		if (process->mm == mm)
 			return process;

 	return NULL;
 }

 static struct kfd_process *find_process(const struct task_struct *thread)
 {
 	struct kfd_process *p;
 	int idx;

 	idx = srcu_read_lock(&kfd_processes_srcu);
 	p = find_process_by_mm(thread->mm);
 	srcu_read_unlock(&kfd_processes_srcu, idx);

 	return p;
 }

 static void kfd_process_wq_release(struct work_struct *work)
 {
 	struct kfd_process_release_work *my_work;
 	struct kfd_process_device *pdd, *temp;
 	struct kfd_process *p;

 	my_work = (struct kfd_process_release_work *) work;

 	p = my_work->p;

 	mutex_lock(&p->mutex);

 	list_for_each_entry_safe(pdd, temp, &p->per_device_data,
 							per_device_list) {
 		amd_iommu_unbind_pasid(pdd->dev->pdev, p->pasid);
 		list_del(&pdd->per_device_list);

 		kfree(pdd);
 	}

 	kfd_pasid_free(p->pasid);

 	mutex_unlock(&p->mutex);

 	mutex_destroy(&p->mutex);

 	kfree(p->queues);

 	kfree(p);

 	kfree((void *)work);
 }

 static void kfd_process_destroy_delayed(struct rcu_head *rcu)
 {
 	struct kfd_process_release_work *work;
 	struct kfd_process *p;

 	BUG_ON(!kfd_process_wq);

 	p = container_of(rcu, struct kfd_process, rcu);
 	BUG_ON(atomic_read(&p->mm->mm_count) <= 0);

 	mmdrop(p->mm);

 	work = (struct kfd_process_release_work *)
 		kmalloc(sizeof(struct kfd_process_release_work), GFP_ATOMIC);

 	if (work) {
 		INIT_WORK((struct work_struct *) work, kfd_process_wq_release);
 		work->p = p;
 		queue_work(kfd_process_wq, (struct work_struct *) work);
 	}
 }

 static void kfd_process_notifier_release(struct mmu_notifier *mn,
 					struct mm_struct *mm)
 {
 	struct kfd_process *p;

 	/*
 	 * The kfd_process structure can not be free because the
 	 * mmu_notifier srcu is read locked
 	 */
 	p = container_of(mn, struct kfd_process, mmu_notifier);
 	BUG_ON(p->mm != mm);

 	mutex_lock(&kfd_processes_mutex);
 	hash_del_rcu(&p->kfd_processes);
 	mutex_unlock(&kfd_processes_mutex);
 	synchronize_srcu(&kfd_processes_srcu);

 	mutex_lock(&p->mutex);

 	/* In case our notifier is called before IOMMU notifier */
 	pqm_uninit(&p->pqm);

 	mutex_unlock(&p->mutex);

 	/*
 	 * Because we drop mm_count inside kfd_process_destroy_delayed
 	 * and because the mmu_notifier_unregister function also drop
 	 * mm_count we need to take an extra count here.
 	 */
 	atomic_inc(&p->mm->mm_count);
 	mmu_notifier_unregister_no_release(&p->mmu_notifier, p->mm);
 	mmu_notifier_call_srcu(&p->rcu, &kfd_process_destroy_delayed);
 }

 static const struct mmu_notifier_ops kfd_process_mmu_notifier_ops = {
 	.release = kfd_process_notifier_release,
 };

 static struct kfd_process *create_process(const struct task_struct *thread)
 {
 	struct kfd_process *process;
 	int err = -ENOMEM;

 	process = kzalloc(sizeof(*process), GFP_KERNEL);

 	if (!process)
 		goto err_alloc_process;

 	process->queues = kmalloc_array(INITIAL_QUEUE_ARRAY_SIZE,
 					sizeof(process->queues[0]), GFP_KERNEL);
 	if (!process->queues)
 		goto err_alloc_queues;

 	process->pasid = kfd_pasid_alloc();
 	if (process->pasid == 0)
 		goto err_alloc_pasid;

 	mutex_init(&process->mutex);

 	process->mm = thread->mm;

 	/* register notifier */
 	process->mmu_notifier.ops = &kfd_process_mmu_notifier_ops;
 	err = __mmu_notifier_register(&process->mmu_notifier, process->mm);
 	if (err)
 		goto err_mmu_notifier;

 	hash_add_rcu(kfd_processes_table, &process->kfd_processes,
 			(uintptr_t)process->mm);

 	process->lead_thread = thread->group_leader;

 	process->queue_array_size = INITIAL_QUEUE_ARRAY_SIZE;

 	INIT_LIST_HEAD(&process->per_device_data);

 	err = pqm_init(&process->pqm, process);
 	if (err != 0)
 		goto err_process_pqm_init;

 	return process;

 err_process_pqm_init:
 	hash_del_rcu(&process->kfd_processes);
 	synchronize_rcu();
 	mmu_notifier_unregister_no_release(&process->mmu_notifier, process->mm);
 err_mmu_notifier:
 	kfd_pasid_free(process->pasid);
 err_alloc_pasid:
 	kfree(process->queues);
 err_alloc_queues:
 	kfree(process);
 err_alloc_process:
 	return ERR_PTR(err);
 }

 struct kfd_process_device *kfd_get_process_device_data(struct kfd_dev *dev,
 							struct kfd_process *p,
 							int create_pdd)
 {
 	struct kfd_process_device *pdd = NULL;

 	list_for_each_entry(pdd, &p->per_device_data, per_device_list)
 		if (pdd->dev == dev)
 			return pdd;

 	if (create_pdd) {
 		pdd = kzalloc(sizeof(*pdd), GFP_KERNEL);
 		if (pdd != NULL) {
 			pdd->dev = dev;
 			INIT_LIST_HEAD(&pdd->qpd.queues_list);
 			INIT_LIST_HEAD(&pdd->qpd.priv_queue_list);
 			pdd->qpd.dqm = dev->dqm;
 			list_add(&pdd->per_device_list, &p->per_device_data);
 		}
 	}

 	return pdd;
 }

 /*
  * Direct the IOMMU to bind the process (specifically the pasid->mm)
  * to the device.
  * Unbinding occurs when the process dies or the device is removed.
  *
  * Assumes that the process lock is held.
  */
 struct kfd_process_device *kfd_bind_process_to_device(struct kfd_dev *dev,
 							struct kfd_process *p)
 {
 	struct kfd_process_device *pdd = kfd_get_process_device_data(dev, p, 1);
 	int err;

 	if (pdd == NULL)
 		return ERR_PTR(-ENOMEM);

 	if (pdd->bound)
 		return pdd;

 	err = amd_iommu_bind_pasid(dev->pdev, p->pasid, p->lead_thread);
 	if (err < 0)
 		return ERR_PTR(err);

 	pdd->bound = true;

 	return pdd;
 }

 void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid)
 {
 	struct kfd_process *p;
 	struct kfd_process_device *pdd;
 	int idx, i;

 	BUG_ON(dev == NULL);

 	idx = srcu_read_lock(&kfd_processes_srcu);

 	hash_for_each_rcu(kfd_processes_table, i, p, kfd_processes)
 		if (p->pasid == pasid)
 			break;

 	srcu_read_unlock(&kfd_processes_srcu, idx);

 	BUG_ON(p->pasid != pasid);

 	mutex_lock(&p->mutex);

 	pqm_uninit(&p->pqm);

 	pdd = kfd_get_process_device_data(dev, p, 0);

 	/*
 	 * Just mark pdd as unbound, because we still need it to call
 	 * amd_iommu_unbind_pasid() in when the process exits.
 	 * We don't call amd_iommu_unbind_pasid() here
 	 * because the IOMMU called us.
 	 */
 	if (pdd)
 		pdd->bound = false;

 	mutex_unlock(&p->mutex);
 }

 struct kfd_process_device *kfd_get_first_process_device_data(struct kfd_process *p)
 {
 	return list_first_entry(&p->per_device_data,
 				struct kfd_process_device,
 				per_device_list);
 }

 struct kfd_process_device *kfd_get_next_process_device_data(struct kfd_process *p,
 						struct kfd_process_device *pdd)
 {
 	if (list_is_last(&pdd->per_device_list, &p->per_device_data))
 		return NULL;
 	return list_next_entry(pdd, per_device_list);
 }

 bool kfd_has_process_device_data(struct kfd_process *p)
 {
 	return !(list_empty(&p->per_device_data));
 }
	/*
	* Copyright 2014 Advanced Micro Devices, Inc.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	*/

	#include <linux/mutex.h>
	#include <linux/log2.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/amd-iommu.h>
	#include <linux/notifier.h>
	struct mm_struct;

	#include "kfd_priv.h"

	/*
	* Initial size for the array of queues.
	* The allocated size is doubled each time
	* it is exceeded up to MAX_PROCESS_QUEUES.
	*/
	#define INITIAL_QUEUE_ARRAY_SIZE 16

	/*
	* List of struct kfd_process (field kfd_process).
	* Unique/indexed by mm_struct*
	*/
	#define KFD_PROCESS_TABLE_SIZE 5 /* bits: 32 entries */
	static DEFINE_HASHTABLE(kfd_processes_table, KFD_PROCESS_TABLE_SIZE);
	static DEFINE_MUTEX(kfd_processes_mutex);

	DEFINE_STATIC_SRCU(kfd_processes_srcu);

	static struct workqueue_struct *kfd_process_wq;

	struct kfd_process_release_work {
	struct work_struct kfd_work;
	struct kfd_process *p;
	};

	static struct kfd_process find_process(const struct task_struct thread);
	static struct kfd_process create_process(const struct task_struct thread);

	void kfd_process_create_wq(void)
	{
	if (!kfd_process_wq)
	kfd_process_wq = create_workqueue("kfd_process_wq");
	}

	void kfd_process_destroy_wq(void)
	{
	if (kfd_process_wq) {
	flush_workqueue(kfd_process_wq);
	destroy_workqueue(kfd_process_wq);
	kfd_process_wq = NULL;
	}
	}

	struct kfd_process kfd_create_process(const struct task_struct thread)
	{
	struct kfd_process *process;

	BUG_ON(!kfd_process_wq);

	if (thread->mm == NULL)
	return ERR_PTR(-EINVAL);

	/* Only the pthreads threading model is supported. */
	if (thread->group_leader->mm != thread->mm)
	return ERR_PTR(-EINVAL);

	/* Take mmap_sem because we call __mmu_notifier_register inside */
	down_write(&thread->mm->mmap_sem);

	/*
	* take kfd processes mutex before starting of process creation
	* so there won't be a case where two threads of the same process
	* create two kfd_process structures
	*/
	mutex_lock(&kfd_processes_mutex);

	/* A prior open of /dev/kfd could have already created the process. */
	process = find_process(thread);
	if (process)
	pr_debug("kfd: process already found\n");

	if (!process)
	process = create_process(thread);

	mutex_unlock(&kfd_processes_mutex);

	up_write(&thread->mm->mmap_sem);

	return process;
	}

	struct kfd_process kfd_get_process(const struct task_struct thread)
	{
	struct kfd_process *process;

	if (thread->mm == NULL)
	return ERR_PTR(-EINVAL);

	/* Only the pthreads threading model is supported. */
	if (thread->group_leader->mm != thread->mm)
	return ERR_PTR(-EINVAL);

	process = find_process(thread);

	return process;
	}

	static struct kfd_process find_process_by_mm(const struct mm_struct mm)
	{
	struct kfd_process *process;

	hash_for_each_possible_rcu(kfd_processes_table, process,
	kfd_processes, (uintptr_t)mm)
	if (process->mm == mm)
	return process;

	return NULL;
	}

	static struct kfd_process find_process(const struct task_struct thread)
	{
	struct kfd_process *p;
	int idx;

	idx = srcu_read_lock(&kfd_processes_srcu);
	p = find_process_by_mm(thread->mm);
	srcu_read_unlock(&kfd_processes_srcu, idx);

	return p;
	}

	static void kfd_process_wq_release(struct work_struct *work)
	{
	struct kfd_process_release_work *my_work;
	struct kfd_process_device pdd, temp;
	struct kfd_process *p;

	my_work = (struct kfd_process_release_work *) work;

	p = my_work->p;

	mutex_lock(&p->mutex);

	list_for_each_entry_safe(pdd, temp, &p->per_device_data,
	per_device_list) {
	amd_iommu_unbind_pasid(pdd->dev->pdev, p->pasid);
	list_del(&pdd->per_device_list);

	kfree(pdd);
	}

	kfd_pasid_free(p->pasid);

	mutex_unlock(&p->mutex);

	mutex_destroy(&p->mutex);

	kfree(p->queues);

	kfree(p);

	kfree((void *)work);
	}

	static void kfd_process_destroy_delayed(struct rcu_head *rcu)
	{
	struct kfd_process_release_work *work;
	struct kfd_process *p;

	BUG_ON(!kfd_process_wq);

	p = container_of(rcu, struct kfd_process, rcu);
	BUG_ON(atomic_read(&p->mm->mm_count) <= 0);

	mmdrop(p->mm);

	work = (struct kfd_process_release_work *)
	kmalloc(sizeof(struct kfd_process_release_work), GFP_ATOMIC);

	if (work) {
	INIT_WORK((struct work_struct *) work, kfd_process_wq_release);
	work->p = p;
	queue_work(kfd_process_wq, (struct work_struct *) work);
	}
	}

	static void kfd_process_notifier_release(struct mmu_notifier *mn,
	struct mm_struct *mm)
	{
	struct kfd_process *p;

	/*
	* The kfd_process structure can not be free because the
	* mmu_notifier srcu is read locked
	*/
	p = container_of(mn, struct kfd_process, mmu_notifier);
	BUG_ON(p->mm != mm);

	mutex_lock(&kfd_processes_mutex);
	hash_del_rcu(&p->kfd_processes);
	mutex_unlock(&kfd_processes_mutex);
	synchronize_srcu(&kfd_processes_srcu);

	mutex_lock(&p->mutex);

	/* In case our notifier is called before IOMMU notifier */
	pqm_uninit(&p->pqm);

	mutex_unlock(&p->mutex);

	/*
	* Because we drop mm_count inside kfd_process_destroy_delayed
	* and because the mmu_notifier_unregister function also drop
	* mm_count we need to take an extra count here.
	*/
	atomic_inc(&p->mm->mm_count);
	mmu_notifier_unregister_no_release(&p->mmu_notifier, p->mm);
	mmu_notifier_call_srcu(&p->rcu, &kfd_process_destroy_delayed);
	}

	static const struct mmu_notifier_ops kfd_process_mmu_notifier_ops = {
	.release = kfd_process_notifier_release,
	};

	static struct kfd_process create_process(const struct task_struct thread)
	{
	struct kfd_process *process;
	int err = -ENOMEM;

	process = kzalloc(sizeof(*process), GFP_KERNEL);

	if (!process)
	goto err_alloc_process;

	process->queues = kmalloc_array(INITIAL_QUEUE_ARRAY_SIZE,
	sizeof(process->queues[0]), GFP_KERNEL);
	if (!process->queues)
	goto err_alloc_queues;

	process->pasid = kfd_pasid_alloc();
	if (process->pasid == 0)
	goto err_alloc_pasid;

	mutex_init(&process->mutex);

	process->mm = thread->mm;

	/* register notifier */
	process->mmu_notifier.ops = &kfd_process_mmu_notifier_ops;
	err = __mmu_notifier_register(&process->mmu_notifier, process->mm);
	if (err)
	goto err_mmu_notifier;

	hash_add_rcu(kfd_processes_table, &process->kfd_processes,
	(uintptr_t)process->mm);

	process->lead_thread = thread->group_leader;

	process->queue_array_size = INITIAL_QUEUE_ARRAY_SIZE;

	INIT_LIST_HEAD(&process->per_device_data);

	err = pqm_init(&process->pqm, process);
	if (err != 0)
	goto err_process_pqm_init;

	return process;

	err_process_pqm_init:
	hash_del_rcu(&process->kfd_processes);
	synchronize_rcu();
	mmu_notifier_unregister_no_release(&process->mmu_notifier, process->mm);
	err_mmu_notifier:
	kfd_pasid_free(process->pasid);
	err_alloc_pasid:
	kfree(process->queues);
	err_alloc_queues:
	kfree(process);
	err_alloc_process:
	return ERR_PTR(err);
	}

	struct kfd_process_device kfd_get_process_device_data(struct kfd_dev dev,
	struct kfd_process *p,
	int create_pdd)
	{
	struct kfd_process_device *pdd = NULL;

	list_for_each_entry(pdd, &p->per_device_data, per_device_list)
	if (pdd->dev == dev)
	return pdd;

	if (create_pdd) {
	pdd = kzalloc(sizeof(*pdd), GFP_KERNEL);
	if (pdd != NULL) {
	pdd->dev = dev;
	INIT_LIST_HEAD(&pdd->qpd.queues_list);
	INIT_LIST_HEAD(&pdd->qpd.priv_queue_list);
	pdd->qpd.dqm = dev->dqm;
	list_add(&pdd->per_device_list, &p->per_device_data);
	}
	}

	return pdd;
	}

	/*
	* Direct the IOMMU to bind the process (specifically the pasid->mm)
	* to the device.
	* Unbinding occurs when the process dies or the device is removed.
	*
	* Assumes that the process lock is held.
	*/
	struct kfd_process_device kfd_bind_process_to_device(struct kfd_dev dev,
	struct kfd_process *p)
	{
	struct kfd_process_device *pdd = kfd_get_process_device_data(dev, p, 1);
	int err;

	if (pdd == NULL)
	return ERR_PTR(-ENOMEM);

	if (pdd->bound)
	return pdd;

	err = amd_iommu_bind_pasid(dev->pdev, p->pasid, p->lead_thread);
	if (err < 0)
	return ERR_PTR(err);

	pdd->bound = true;

	return pdd;
	}

	void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid)
	{
	struct kfd_process *p;
	struct kfd_process_device *pdd;
	int idx, i;

	BUG_ON(dev == NULL);

	idx = srcu_read_lock(&kfd_processes_srcu);

	hash_for_each_rcu(kfd_processes_table, i, p, kfd_processes)
	if (p->pasid == pasid)
	break;

	srcu_read_unlock(&kfd_processes_srcu, idx);

	BUG_ON(p->pasid != pasid);

	mutex_lock(&p->mutex);

	pqm_uninit(&p->pqm);

	pdd = kfd_get_process_device_data(dev, p, 0);

	/*
	* Just mark pdd as unbound, because we still need it to call
	* amd_iommu_unbind_pasid() in when the process exits.
	* We don't call amd_iommu_unbind_pasid() here
	* because the IOMMU called us.
	*/
	if (pdd)
	pdd->bound = false;

	mutex_unlock(&p->mutex);
	}

	struct kfd_process_device kfd_get_first_process_device_data(struct kfd_process p)
	{
	return list_first_entry(&p->per_device_data,
	struct kfd_process_device,
	per_device_list);
	}

	struct kfd_process_device kfd_get_next_process_device_data(struct kfd_process p,
	struct kfd_process_device *pdd)
	{
	if (list_is_last(&pdd->per_device_list, &p->per_device_data))
	return NULL;
	return list_next_entry(pdd, per_device_list);
	}

	bool kfd_has_process_device_data(struct kfd_process *p)
	{
	return !(list_empty(&p->per_device_data));
	}