From: Xiaogang Chen <[email protected]> kfd process kref count(process->ref) is initialized to 1 by kref_init. After it is created not need to increaes its kref. Instad add kfd process kref at kfd process mmu notifier allocation since we decrease the ref 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 kfd node close operation. Signed-off-by: Xiaogang Chen <[email protected]> --- drivers/gpu/drm/amd/amdkfd/kfd_process.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c index d07acf1b2f93..78bf918abf92 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c @@ -850,8 +850,10 @@ 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 { @@ -899,8 +901,6 @@ 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); @@ -1191,7 +1191,12 @@ static struct mmu_notifier *kfd_process_alloc_notifier(struct mm_struct *mm) srcu_read_unlock(&kfd_processes_srcu, idx); - return p ? &p->mmu_notifier : ERR_PTR(-ESRCH); + if (p) { + kref_get(&p->ref); + return &p->mmu_notifier; + } + + return ERR_PTR(-ESRCH); } static void kfd_process_free_notifier(struct mmu_notifier *mn) -- 2.25.1
