Re: [RFC PATCH 2/4] DRM: Add support of AI Processor Unit (APU)

On Fri, 17 Sep 2021 14:59:43 +0200 Alexandre Bailon wrote:

+static DEFINE_IDA(req_ida); +static LIST_HEAD(complete_node);

I see accesses to complete_node in apu_drm_callback(), apu_job_timedout() and ioctl_gem_dequeue() without working out the serialization to avoid list corruption. Can you add a comment to specify it?

+int apu_drm_callback(struct apu_core *apu_core, void *data, int len) +{

• struct apu_request *apu_req, *tmp;
• struct apu_dev_request *hdr = data;
• unsigned long flags;
• spin_lock_irqsave(&apu_core->ctx_lock, flags);
• list_for_each_entry_safe(apu_req, tmp, &apu_core->requests, node) {

• struct apu_job *job = apu_req->job;
  

• if (job && hdr->id == job->id) {
  

• 	kref_get(&job->refcount);
  

• 	job->result = hdr->result;
  

• 	if (job->size_out)
  

• 		memcpy(job->data_out, hdr->data + job->size_in,
  

• 		       min(job->size_out, hdr->size_out));
  

• 	job->size_out = hdr->size_out;
  

• 	list_add(&job->node, &complete_node);
  

• 	list_del(&apu_req->node);
  

• 	ida_simple_remove(&req_ida, hdr->id);
  

• 	kfree(apu_req);
  

• 	drm_send_event(job->apu_drm->drm,
  

• 		       &job->event->pending_event);
  

• 	dma_fence_signal_locked(job->done_fence);
  

• }
  

• }
• spin_unlock_irqrestore(&apu_core->ctx_lock, flags);
• return 0;

+}