[PATCH] drm/xe/vm: Use for_each_tlb_inval() to calculate invalidation fences

[Matt Roper <matthew.d.roper@intel.com>]

ops_execute() calculates the size of a fence array based on
XE_MAX_GT_PER_TILE, while the code that actually fills in the fence
array uses a for_each_tlb_inval() iterator.  This works out okay today
since both approaches come up with the same number of invalidation
fences (2: primary GT invalidation + media GT invalidation), but could
be problematic in the future if there isn't a 1:1 relationship between
TLBs needing invalidation and potential GTs on the tile.

Adjust the allocation code to use the same for_each_tlb_inval()
counting logic as the code that fills the array to future-proof the
code.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
v2:
 - Add missing local variable movement that I forgot to commit before
   sending v1.

 drivers/gpu/drm/xe/xe_vm.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 7cac646bdf1c..f9989a7a710c 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -3104,19 +3104,19 @@ static struct dma_fence *ops_execute(struct xe_vm *vm,
 	struct dma_fence *fence = NULL;
 	struct dma_fence **fences = NULL;
 	struct dma_fence_array *cf = NULL;
-	int number_tiles = 0, current_fence = 0, n_fence = 0, err;
+	int number_tiles = 0, current_fence = 0, n_fence = 0, err, i;
 	u8 id;
 
 	number_tiles = vm_ops_setup_tile_args(vm, vops);
 	if (number_tiles == 0)
 		return ERR_PTR(-ENODATA);
 
-	if (vops->flags & XE_VMA_OPS_FLAG_SKIP_TLB_WAIT) {
-		for_each_tile(tile, vm->xe, id)
-			++n_fence;
-	} else {
-		for_each_tile(tile, vm->xe, id)
-			n_fence += (1 + XE_MAX_GT_PER_TILE);
+	for_each_tile(tile, vm->xe, id) {
+		++n_fence;
+
+		if (!(vops->flags & XE_VMA_OPS_FLAG_SKIP_TLB_WAIT))
+			for_each_tlb_inval(i)
+				++n_fence;
 	}
 
 	fences = kmalloc_array(n_fence, sizeof(*fences), GFP_KERNEL);
@@ -3146,7 +3146,6 @@ static struct dma_fence *ops_execute(struct xe_vm *vm,
 
 	for_each_tile(tile, vm->xe, id) {
 		struct xe_exec_queue *q = vops->pt_update_ops[tile->id].q;
-		int i;
 
 		fence = NULL;
 		if (!vops->pt_update_ops[id].num_ops)
-- 
2.51.1