[PATCH v3 2/2] drm/xe: Use dma-fence array for media GT TLB invalidations in PT code

[Matthew Brost]

Using a chain fence is problematic as these cannot be installed in
timeout drm sync objects. Use a dma-fence-array instead at the cost of
an extra failure point.

Also fixup reserve fence count to include media GT invalidation fence.

v2:
 - Fix reserve fence count (Casey Bowman)
v3:
 - Prealloc dma fence array (CI)

Fixes: 40520283e0fd ("drm/xe: Invalidate media_gt TLBs in PT code")
Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/xe_pt.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
index 6c6714af3d5d..2e35444a85b0 100644
--- a/drivers/gpu/drm/xe/xe_pt.c
+++ b/drivers/gpu/drm/xe/xe_pt.c
@@ -3,7 +3,7 @@
  * Copyright © 2022 Intel Corporation
  */
 
-#include <linux/dma-fence-chain.h>
+#include <linux/dma-fence-array.h>
 
 #include "xe_pt.h"
 
@@ -1629,9 +1629,11 @@ xe_pt_update_ops_rfence_interval(struct xe_vm_pgtable_update_ops *pt_update_ops,
 
 static int vma_reserve_fences(struct xe_device *xe, struct xe_vma *vma)
 {
+	int shift = xe_device_get_root_tile(xe)->media_gt ? 1 : 0;
+
 	if (!xe_vma_has_no_bo(vma) && !xe_vma_bo(vma)->vm)
 		return dma_resv_reserve_fences(xe_vma_bo(vma)->ttm.base.resv,
-					       xe->info.tile_count);
+					       xe->info.tile_count << shift);
 
 	return 0;
 }
@@ -1818,6 +1820,7 @@ int xe_pt_update_ops_prepare(struct xe_tile *tile, struct xe_vma_ops *vops)
 	struct xe_vm_pgtable_update_ops *pt_update_ops =
 		&vops->pt_update_ops[tile->id];
 	struct xe_vma_op *op;
+	int shift = tile->media_gt ? 1 : 0;
 	int err;
 
 	lockdep_assert_held(&vops->vm->lock);
@@ -1826,7 +1829,7 @@ int xe_pt_update_ops_prepare(struct xe_tile *tile, struct xe_vma_ops *vops)
 	xe_pt_update_ops_init(pt_update_ops);
 
 	err = dma_resv_reserve_fences(xe_vm_resv(vops->vm),
-				      tile_to_xe(tile)->info.tile_count);
+				      tile_to_xe(tile)->info.tile_count << shift);
 	if (err)
 		return err;
 
@@ -1983,7 +1986,8 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
 		&vops->pt_update_ops[tile->id];
 	struct dma_fence *fence;
 	struct invalidation_fence *ifence = NULL, *mfence = NULL;
-	struct dma_fence_chain *chain_fence = NULL;
+	struct dma_fence **fences = NULL;
+	struct dma_fence_array *cf = NULL;
 	struct xe_range_fence *rfence;
 	struct xe_vma_op *op;
 	int err = 0, i;
@@ -2022,8 +2026,13 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
 				err = -ENOMEM;
 				goto free_ifence;
 			}
-			chain_fence = dma_fence_chain_alloc();
-			if (!chain_fence) {
+			fences = kmalloc_array(2, sizeof(*fences), GFP_KERNEL);
+			if (!fences) {
+				err = -ENOMEM;
+				goto free_ifence;
+			}
+			cf = dma_fence_array_alloc(2);
+			if (!cf) {
 				err = -ENOMEM;
 				goto free_ifence;
 			}
@@ -2068,9 +2077,13 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
 			invalidation_fence_init(tile->media_gt, mfence, fence,
 						pt_update_ops->start,
 						pt_update_ops->last, vm->usm.asid);
-			dma_fence_chain_init(chain_fence, &ifence->base.base,
-					     &mfence->base.base, 0);
-			fence = &chain_fence->base;
+			fences[0] = &ifence->base.base;
+			fences[1] = &mfence->base.base;
+			dma_fence_array_arm(cf, 2, fences,
+					    vm->composite_fence_ctx,
+					    vm->composite_fence_seqno++,
+					    false);
+			fence = &cf->base;
 		} else {
 			fence = &ifence->base.base;
 		}
@@ -2108,7 +2121,8 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
 free_rfence:
 	kfree(rfence);
 free_ifence:
-	dma_fence_chain_free(chain_fence);
+	kfree(cf);
+	kfree(fences);
 	kfree(mfence);
 	kfree(ifence);
 kill_vm_tile1:
-- 
2.34.1