drm/amdgpu: stop reserving the BO in the MMU callback v3

Instead take the callback lock during the final parts of CS.

This should solve the last remaining locking order problems with BO reservations.

v2: rebase, make dummy functions static inline
v3: add one more missing inline and comments

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 21 insertions, 9 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
index 6d216abd0e1d..99edb40b5f99 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
@@ -106,6 +106,25 @@ static void amdgpu_mn_release(struct mmu_notifier *mn,
         schedule_work(&rmn->work);
 }
 
+
+/**
+ * amdgpu_mn_lock - take the write side lock for this mn
+ */
+void amdgpu_mn_lock(struct amdgpu_mn *mn)
+{
+        if (mn)
+                down_write(&mn->lock);
+}
+
+/**
+ * amdgpu_mn_unlock - drop the write side lock for this mn
+ */
+void amdgpu_mn_unlock(struct amdgpu_mn *mn)
+{
+        if (mn)
+                up_write(&mn->lock);
+}
+
 /**
  * amdgpu_mn_invalidate_node - unmap all BOs of a node
  *
@@ -126,20 +145,12 @@ static void amdgpu_mn_invalidate_node(struct amdgpu_mn_node *node,
                 if (!amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm, start, end))
                         continue;
 
-                r = amdgpu_bo_reserve(bo, true);
-                if (r) {
-                        DRM_ERROR("(%ld) failed to reserve user bo\n", r);
-                        continue;
-                }
-
                 r = reservation_object_wait_timeout_rcu(bo->tbo.resv,
                         true, false, MAX_SCHEDULE_TIMEOUT);
                 if (r <= 0)
                         DRM_ERROR("(%ld) failed to wait for user bo\n", r);
 
                 amdgpu_ttm_tt_mark_user_pages(bo->tbo.ttm);
-
-                amdgpu_bo_unreserve(bo);
         }
 }
 
@@ -223,7 +234,7 @@ static const struct mmu_notifier_ops amdgpu_mn_ops = {
  *
  * Creates a notifier context for current->mm.
  */
-static struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev)
+struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev)
 {
         struct mm_struct *mm = current->mm;
         struct amdgpu_mn *rmn;
@@ -368,3 +379,4 @@ void amdgpu_mn_unregister(struct amdgpu_bo *bo)
         up_write(&rmn->lock);
         mutex_unlock(&adev->mn_lock);
 }
+