On 6/17/2022 4:33 PM, Dmitry Baryshkov wrote:
The array of CRTC in the struct msm_drm_private duplicates a list of
CRTCs in the drm_device. Drop it and use the existing list for CRTC
enumeration.

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Dmitry Baryshkov <[email protected]>
---
  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c  |  2 +-
  drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c |  2 +-
  drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c |  2 +-
  drivers/gpu/drm/msm/msm_drv.c            | 44 +++++++++++++-----------
  drivers/gpu/drm/msm/msm_drv.h            |  3 +-
  5 files changed, 27 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c 
b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index e23e2552e802..e79f0a8817ac 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -806,7 +806,7 @@ static int _dpu_kms_drm_obj_init(struct dpu_kms *dpu_kms)
                        ret = PTR_ERR(crtc);
                        return ret;
                }
-               priv->crtcs[priv->num_crtcs++] = crtc;
+               priv->num_crtcs++;
        }
/* All CRTCs are compatible with all encoders */
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c 
b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
index fb48c8c19ec3..7449c1693e45 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
@@ -337,7 +337,7 @@ static int modeset_init(struct mdp4_kms *mdp4_kms)
                        goto fail;
                }
- priv->crtcs[priv->num_crtcs++] = crtc;
+               priv->num_crtcs++;
        }
/*
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c 
b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
index 3d5621a68f85..36808990f840 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
@@ -497,7 +497,7 @@ static int modeset_init(struct mdp5_kms *mdp5_kms)
                        DRM_DEV_ERROR(dev->dev, "failed to construct crtc %d 
(%d)\n", i, ret);
                        goto fail;
                }
-               priv->crtcs[priv->num_crtcs++] = crtc;
+               priv->num_crtcs++;
        }
/*
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 1aab6bf86278..567e77dae43b 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -149,7 +149,7 @@ static void msm_irq_uninstall(struct drm_device *dev)
struct msm_vblank_work {
        struct work_struct work;
-       int crtc_id;
+       struct drm_crtc *crtc;
        bool enable;
        struct msm_drm_private *priv;
  };
@@ -162,15 +162,15 @@ static void vblank_ctrl_worker(struct work_struct *work)
        struct msm_kms *kms = priv->kms;

Is there any chance of vbl_work->crtc becoming NULL before this gets executed?

So do we need to protect this like

if (vbl_work->enable && vbl_work->crtc)

Because the layers below this dont seem to have NULL protection.


        if (vbl_work->enable)
-               kms->funcs->enable_vblank(kms, priv->crtcs[vbl_work->crtc_id]);
+               kms->funcs->enable_vblank(kms, vbl_work->crtc);
        else
-               kms->funcs->disable_vblank(kms,   
priv->crtcs[vbl_work->crtc_id]);
+               kms->funcs->disable_vblank(kms,   vbl_work->crtc);
kfree(vbl_work);
  }
static int vblank_ctrl_queue_work(struct msm_drm_private *priv,
-                                       int crtc_id, bool enable)
+                                       struct drm_crtc *crtc, bool enable)
  {
        struct msm_vblank_work *vbl_work;
@@ -180,7 +180,7 @@ static int vblank_ctrl_queue_work(struct msm_drm_private *priv, INIT_WORK(&vbl_work->work, vblank_ctrl_worker); - vbl_work->crtc_id = crtc_id;
+       vbl_work->crtc = crtc;
        vbl_work->enable = enable;
        vbl_work->priv = priv;
@@ -354,7 +354,8 @@ static int msm_drm_init(struct device *dev, const struct drm_driver *drv)
        struct msm_drm_private *priv = dev_get_drvdata(dev);
        struct drm_device *ddev;
        struct msm_kms *kms;
-       int ret, i;
+       struct drm_crtc *crtc;
+       int ret;
if (drm_firmware_drivers_only())
                return -ENODEV;
@@ -427,20 +428,23 @@ static int msm_drm_init(struct device *dev, const struct 
drm_driver *drv)
        ddev->mode_config.funcs = &mode_config_funcs;
        ddev->mode_config.helper_private = &mode_config_helper_funcs;
- for (i = 0; i < priv->num_crtcs; i++) {
+       drm_for_each_crtc(crtc, ddev) {
+               struct msm_drm_thread *ev_thread;
+
                /* initialize event thread */
-               priv->event_thread[i].crtc_id = priv->crtcs[i]->base.id;
-               priv->event_thread[i].dev = ddev;
-               priv->event_thread[i].worker = kthread_create_worker(0,
-                       "crtc_event:%d", priv->event_thread[i].crtc_id);
-               if (IS_ERR(priv->event_thread[i].worker)) {
-                       ret = PTR_ERR(priv->event_thread[i].worker);
+               ev_thread = &priv->event_thread[drm_crtc_index(crtc)];
+               ev_thread->crtc = crtc;
+               ev_thread->dev = ddev;
+               ev_thread->worker = kthread_create_worker(0,
+                       "crtc_event:%d", ev_thread->crtc->base.id);

Please correct me if wrong.

Today, other than just populating the name for the worker is the ev_thread->crtc used anywhere?

If so, can we just drop crtc from msm_drm_thread and while creating the worker just use kthread_create_worker(0, "crtc_event:%d", crtc->base.id);

+               if (IS_ERR(ev_thread->worker)) {
+                       ret = PTR_ERR(ev_thread->worker);
                        DRM_DEV_ERROR(dev, "failed to create crtc_event 
kthread\n");
-                       priv->event_thread[i].worker = NULL;
+                       ev_thread->worker = NULL;
                        goto err_msm_uninit;
                }
- sched_set_fifo(priv->event_thread[i].worker->task);
+               sched_set_fifo(ev_thread->worker->task);
        }
ret = drm_vblank_init(ddev, priv->num_crtcs);
@@ -563,25 +567,23 @@ static void msm_postclose(struct drm_device *dev, struct 
drm_file *file)
  int msm_crtc_enable_vblank(struct drm_crtc *crtc)
  {
        struct drm_device *dev = crtc->dev;
-       unsigned int pipe = crtc->index;
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_kms *kms = priv->kms;
        if (!kms)
                return -ENXIO;
-       drm_dbg_vbl(dev, "crtc=%u", pipe);
-       return vblank_ctrl_queue_work(priv, pipe, true);
+       drm_dbg_vbl(dev, "crtc=%u", crtc->base.id);
+       return vblank_ctrl_queue_work(priv, crtc, true);
  }
void msm_crtc_disable_vblank(struct drm_crtc *crtc)
  {
        struct drm_device *dev = crtc->dev;
-       unsigned int pipe = crtc->index;
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_kms *kms = priv->kms;
        if (!kms)
                return;
-       drm_dbg_vbl(dev, "crtc=%u", pipe);
-       vblank_ctrl_queue_work(priv, pipe, false);
+       drm_dbg_vbl(dev, "crtc=%u", crtc->base.id);
+       vblank_ctrl_queue_work(priv, crtc, false);
  }
/*
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index 08388d742d65..0e98b6f161df 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -102,7 +102,7 @@ struct msm_display_topology {
  /* Commit/Event thread specific structure */
  struct msm_drm_thread {
        struct drm_device *dev;
-       unsigned int crtc_id;
+       struct drm_crtc *crtc;
        struct kthread_worker *worker;
  };
@@ -178,7 +178,6 @@ struct msm_drm_private {
        struct workqueue_struct *wq;
unsigned int num_crtcs;
-       struct drm_crtc *crtcs[MAX_CRTCS];
struct msm_drm_thread event_thread[MAX_CRTCS];

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