drm/i915: Add ww context to intel_dpt_pin, v2.

Ensure i915_vma_pin_iomap and vma_unpin are done with dpt->obj lock held.

I don't think there's much of a point in merging intel_dpt_pin() with
intel_pin_fb_obj_dpt(), they touch different objects.

Changes since v1:
- Fix using the wrong pointer to retrieve error code (Julia)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210929085950.3063191-1-maarten.lankhorst@linux.intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_dpt.c b/drivers/gpu/drm/i915/display/intel_dpt.c
index de62bd7..8f7b1f7 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dpt.c
+++ b/drivers/gpu/drm/i915/display/intel_dpt.c
@@ -121,32 +121,42 @@ struct i915_vma *intel_dpt_pin(struct i915_address_space *vm)
        intel_wakeref_t wakeref;
        struct i915_vma *vma;
        void __iomem *iomem;
+       struct i915_gem_ww_ctx ww;
+       int err;
 
        wakeref = intel_runtime_pm_get(&i915->runtime_pm);
        atomic_inc(&i915->gpu_error.pending_fb_pin);
 
-       vma = i915_gem_object_ggtt_pin(dpt->obj, NULL, 0, 4096,
-                                      HAS_LMEM(i915) ? 0 : PIN_MAPPABLE);
-       if (IS_ERR(vma))
-               goto err;
+       for_i915_gem_ww(&ww, err, true) {
+               err = i915_gem_object_lock(dpt->obj, &ww);
+               if (err)
+                       continue;
 
-       iomem = i915_vma_pin_iomap(vma);
-       i915_vma_unpin(vma);
-       if (IS_ERR(iomem)) {
-               vma = ERR_CAST(iomem);
-               goto err;
-       }
+               vma = i915_gem_object_ggtt_pin_ww(dpt->obj, &ww, NULL, 0, 4096,
+                                                 HAS_LMEM(i915) ? 0 : PIN_MAPPABLE);
+               if (IS_ERR(vma)) {
+                       err = PTR_ERR(vma);
+                       continue;
+               }
+
+               iomem = i915_vma_pin_iomap(vma);
+               i915_vma_unpin(vma);
 
-       dpt->vma = vma;
-       dpt->iomem = iomem;
+               if (IS_ERR(iomem)) {
+                       err = PTR_ERR(iomem);
+                       continue;
+               }
 
-       i915_vma_get(vma);
+               dpt->vma = vma;
+               dpt->iomem = iomem;
+
+               i915_vma_get(vma);
+       }
 
-err:
        atomic_dec(&i915->gpu_error.pending_fb_pin);
        intel_runtime_pm_put(&i915->runtime_pm, wakeref);
 
-       return vma;
+       return err ? ERR_PTR(err) : vma;
 }
 
 void intel_dpt_unpin(struct i915_address_space *vm)