Commit 6cb6d437 authored by Xiaogang Chen's avatar Xiaogang Chen Committed by Alex Deucher
Browse files

drm/amdkfd: change kfd process kref count at creation 



kfd process kref count(process->ref) is initialized to 1 by kref_init. After
it is created not need to increase its kref. Instad add kfd process kref at kfd
process mmu notifier allocation since we already decrease the kref at
free_notifier of mmu_notifier_ops, so pair them.

When user process opens kfd node multiple times the kfd process kref is
increased each time to balance with kfd node close operation.

Signed-off-by: default avatarXiaogang Chen <xiaogang.chen@amd.com>
Reviewed-by: default avatarFelix Kuehling <felix.kuehling@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 408d2081

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

+6 −8
Original line number Diff line number Diff line
@@ -854,8 +854,10 @@ struct kfd_process *kfd_create_process(struct task_struct *thread) 
		goto out;

	}



	/* A prior open of /dev/kfd could have already created the process. */

	process = find_process(thread, false);

	/* A prior open of /dev/kfd could have already created the process.

	 * find_process will increase process kref in this case

	 */

	process = find_process(thread, true);

	if (process) {

		pr_debug("Process already found\n");

	} else {
@@ -903,8 +905,6 @@ struct kfd_process *kfd_create_process(struct task_struct *thread) 
		init_waitqueue_head(&process->wait_irq_drain);

	}

out:

	if (!IS_ERR(process))

		kref_get(&process->ref);

	mutex_unlock(&kfd_processes_mutex);

	mmput(thread->mm);
@@ -1190,10 +1190,8 @@ static void kfd_process_ref_release(struct kref *ref) 


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);

	/* This increments p->ref counter if kfd process p exists */

	struct kfd_process *p = kfd_lookup_process_by_mm(mm);



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

}