drm/ttm: protect against reentrant bind in the drivers

This moves the generic tracking into the drivers and protects
against reentrancy in the drivers. It fixes up radeon and agp
to be able to query the bound status as that is required.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200917043040.146575-2-airlied@gmail.com

3 files changed, 33 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index df6f0b49836b..a6d8de01194a 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -2820,6 +2820,7 @@ extern int radeon_ttm_tt_set_userptr(struct radeon_device *rdev,
 				     uint32_t flags);
 extern bool radeon_ttm_tt_has_userptr(struct radeon_device *rdev, struct ttm_tt *ttm);
 extern bool radeon_ttm_tt_is_readonly(struct radeon_device *rdev, struct ttm_tt *ttm);
+bool radeon_ttm_tt_is_bound(struct ttm_bo_device *bdev, struct ttm_tt *ttm);
 extern void radeon_vram_location(struct radeon_device *rdev, struct radeon_mc *mc, u64 base);
 extern void radeon_gtt_location(struct radeon_device *rdev, struct radeon_mc *mc);
 extern int radeon_resume_kms(struct drm_device *dev, bool resume, bool fbcon);
diff --git a/drivers/gpu/drm/radeon/radeon_mn.c b/drivers/gpu/drm/radeon/radeon_mn.c
index eb46d2220236..97b9b6dd6dd3 100644
--- a/drivers/gpu/drm/radeon/radeon_mn.c
+++ b/drivers/gpu/drm/radeon/radeon_mn.c
@@ -53,7 +53,7 @@ static bool radeon_mn_invalidate(struct mmu_interval_notifier *mn,
 	struct ttm_operation_ctx ctx = { false, false };
 	long r;
 
-	if (!bo->tbo.ttm || !ttm_bo_tt_is_bound(&bo->tbo))
+	if (!bo->tbo.ttm || !radeon_ttm_tt_is_bound(bo->tbo.bdev, bo->tbo.ttm))
 		return true;
 
 	if (!mmu_notifier_range_blockable(range))
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index c6c1008fefd2..fc8bbca28b34 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -420,6 +420,7 @@ struct radeon_ttm_tt {
 	uint64_t			userptr;
 	struct mm_struct		*usermm;
 	uint32_t			userflags;
+	bool bound;
 };
 
 /* prepare the sg table with the user pages */
@@ -513,6 +514,13 @@ static void radeon_ttm_tt_unpin_userptr(struct ttm_bo_device *bdev, struct ttm_t
 	sg_free_table(ttm->sg);
 }
 
+static bool radeon_ttm_backend_is_bound(struct ttm_tt *ttm)
+{
+	struct radeon_ttm_tt *gtt = (void*)ttm;
+
+	return (gtt->bound);
+}
+
 static int radeon_ttm_backend_bind(struct ttm_bo_device *bdev,
 				   struct ttm_tt *ttm,
 				   struct ttm_resource *bo_mem)
@@ -523,6 +531,9 @@ static int radeon_ttm_backend_bind(struct ttm_bo_device *bdev,
 		RADEON_GART_PAGE_WRITE;
 	int r;
 
+	if (gtt->bound)
+		return 0;
+
 	if (gtt->userptr) {
 		radeon_ttm_tt_pin_userptr(bdev, ttm);
 		flags &= ~RADEON_GART_PAGE_WRITE;
@@ -542,6 +553,7 @@ static int radeon_ttm_backend_bind(struct ttm_bo_device *bdev,
 			  ttm->num_pages, (unsigned)gtt->offset);
 		return r;
 	}
+	gtt->bound = true;
 	return 0;
 }
 
@@ -550,10 +562,14 @@ static void radeon_ttm_backend_unbind(struct ttm_bo_device *bdev, struct ttm_tt
 	struct radeon_ttm_tt *gtt = (void *)ttm;
 	struct radeon_device *rdev = radeon_get_rdev(bdev);
 
+	if (!gtt->bound)
+		return;
+
 	radeon_gart_unbind(rdev, gtt->offset, ttm->num_pages);
 
 	if (gtt->userptr)
 		radeon_ttm_tt_unpin_userptr(bdev, ttm);
+	gtt->bound = false;
 }
 
 static void radeon_ttm_backend_destroy(struct ttm_bo_device *bdev, struct ttm_tt *ttm)
@@ -689,12 +705,27 @@ int radeon_ttm_tt_set_userptr(struct radeon_device *rdev,
 	return 0;
 }
 
+bool radeon_ttm_tt_is_bound(struct ttm_bo_device *bdev,
+			    struct ttm_tt *ttm)
+{
+#if IS_ENABLED(CONFIG_AGP)
+	struct radeon_device *rdev = radeon_get_rdev(bdev);
+	if (rdev->flags & RADEON_IS_AGP)
+		return ttm_agp_is_bound(ttm);
+#endif
+	return radeon_ttm_backend_is_bound(ttm);
+}
+
 static int radeon_ttm_tt_bind(struct ttm_bo_device *bdev,
 			      struct ttm_tt *ttm,
 			      struct ttm_resource *bo_mem)
 {
+#if IS_ENABLED(CONFIG_AGP)
 	struct radeon_device *rdev = radeon_get_rdev(bdev);
+#endif
 
+	if (!bo_mem)
+		return -EINVAL;
 #if IS_ENABLED(CONFIG_AGP)
 	if (rdev->flags & RADEON_IS_AGP)
 		return ttm_agp_bind(ttm, bo_mem);