[PATCH v3 2/4] drm/i915/ttm: only fault WILLNEED objects

Matthew Auld
2022-01-06T17:49:46Z

Don't attempt to fault and re-populate purged objects. By some fluke
this passes the dontneed-after-mmap IGT, but for the wrong reasons.

Fixes: cf3e3e86d779 ("drm/i915: Use ttm mmap handling for ttm bo's.")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 923cc7ad8d70..8d61d4538a64 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -883,6 +883,11 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
if (ret)
return ret;

+ if (obj->mm.madv != I915_MADV_WILLNEED) {
+ dma_resv_unlock(bo->base.resv);
+ return VM_FAULT_SIGBUS;
+ }
+
if (drm_dev_enter(dev, &idx)) {
ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
TTM_BO_VM_NUM_PREFAULT);
--
2.31.1