[Intel-gfx] [PATCH] drm/i915: Accomodate for nested dma_resv fence addition

[Nirmoy Das <nirmoy.das@intel.com>]

We have below nested fence slot reservation and then fence addition
to that dma_resv.
dma_resv_reserve_fences() from --> ttm_bo_handle_move_mem()
        dma_resv_reserve_fences() from --> i915_vma_unbind_async()
        dma_resv_add_fence() from --> i915_vma_unbind_async()
dma_resv_add_fence() from -->ttm_bo_move_accel_cleanup()

A nested dma_resv_reserve_fences will not reserve extra slots and if the
BO comes with lots of fences in its dma_resv, we might see:

BUG_ON(fobj->num_fences >= fobj->max_fences);

Suggested-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
---
 drivers/gpu/drm/i915/i915_vma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 7d044888ac33..5ac4c1c2403c 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -2149,7 +2149,7 @@ int i915_vma_unbind_async(struct i915_vma *vma, bool trylock_vm)
 	if (!obj->mm.rsgt)
 		return -EBUSY;
 
-	err = dma_resv_reserve_fences(obj->base.resv, 1);
+	err = dma_resv_reserve_fences(obj->base.resv, 2);
 	if (err)
 		return -EBUSY;
 
-- 
2.38.0