Commit 3248b6d3 authored by Felix Kuehling's avatar Felix Kuehling Committed by Alex Deucher
Browse files

drm/amdkfd: Use mmu_notifier_get 



We use mmu_notifier_put to free the MMU notifier. That needs to be
paired with mmu_notifier_get to work correctly. Othewrise the next patch
would cause a kernel oops.

Signed-off-by: default avatarFelix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: default avatarPhilip Yang <philip.yang@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 263a4feb

drivers/gpu/drm/amd/amdkfd/kfd_process.c

+27 −6
Original line number Diff line number Diff line
@@ -1011,6 +1011,16 @@ static void kfd_process_ref_release(struct kref *ref) 
	queue_work(kfd_process_wq, &p->release_work);

}



static struct mmu_notifier *kfd_process_alloc_notifier(struct mm_struct *mm)

{

	int idx = srcu_read_lock(&kfd_processes_srcu);

	struct kfd_process *p = find_process_by_mm(mm);



	srcu_read_unlock(&kfd_processes_srcu, idx);



	return p ? &p->mmu_notifier : ERR_PTR(-ESRCH);

}



static void kfd_process_free_notifier(struct mmu_notifier *mn)

{

	kfd_unref_process(container_of(mn, struct kfd_process, mmu_notifier));
@@ -1075,6 +1085,7 @@ static void kfd_process_notifier_release(struct mmu_notifier *mn, 


static const struct mmu_notifier_ops kfd_process_mmu_notifier_ops = {

	.release = kfd_process_notifier_release,

	.alloc_notifier = kfd_process_alloc_notifier,

	.free_notifier = kfd_process_free_notifier,

};
@@ -1152,6 +1163,7 @@ static int kfd_process_device_init_cwsr_dgpu(struct kfd_process_device *pdd) 
static struct kfd_process *create_process(const struct task_struct *thread)

{

	struct kfd_process *process;

	struct mmu_notifier *mn;

	int err = -ENOMEM;



	process = kzalloc(sizeof(*process), GFP_KERNEL);
@@ -1182,19 +1194,28 @@ static struct kfd_process *create_process(const struct task_struct *thread) 
	if (err != 0)

		goto err_init_apertures;



	/* Must be last, have to use release destruction after this */

	process->mmu_notifier.ops = &kfd_process_mmu_notifier_ops;

	err = mmu_notifier_register(&process->mmu_notifier, process->mm);

	if (err)

	/* alloc_notifier needs to find the process in the hash table */

	hash_add_rcu(kfd_processes_table, &process->kfd_processes,

			(uintptr_t)process->mm);



	/* MMU notifier registration must be the last call that can fail

	 * because after this point we cannot unwind the process creation.

	 * After this point, mmu_notifier_put will trigger the cleanup by

	 * dropping the last process reference in the free_notifier.

	 */

	mn = mmu_notifier_get(&kfd_process_mmu_notifier_ops, process->mm);

	if (IS_ERR(mn)) {

		err = PTR_ERR(mn);

		goto err_register_notifier;

	}

	BUG_ON(mn != &process->mmu_notifier);



	get_task_struct(process->lead_thread);

	hash_add_rcu(kfd_processes_table, &process->kfd_processes,

			(uintptr_t)process->mm);



	return process;



err_register_notifier:

	hash_del_rcu(&process->kfd_processes);

	kfd_process_free_outstanding_kfd_bos(process);

	kfd_process_destroy_pdds(process);

err_init_apertures: