drm/i915: Don't free shared locks while shared

We are currently sharing the VM reservation locks across a number of
gem objects with page-table memory. Since TTM will individiualize the
reservation locks when freeing objects, including accessing the shared
locks, make sure that the shared locks are not freed until that is done.
For PPGTT we add an additional refcount, for GGTT we take additional
measures to make sure objects sharing the GGTT reservation lock are
freed at GGTT takedown

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210601074654.3103-3-thomas.hellstrom@linux.intel.com

1 files changed, 16 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
index dcb3b299cf4a..efcd5aeac936 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
@@ -745,7 +745,6 @@ static void ggtt_cleanup_hw(struct i915_ggtt *ggtt)
 
 	mutex_unlock(&ggtt->vm.mutex);
 	i915_address_space_fini(&ggtt->vm);
-	dma_resv_fini(&ggtt->vm.resv);
 
 	arch_phys_wc_del(ggtt->mtrr);
 
@@ -767,6 +766,19 @@ void i915_ggtt_driver_release(struct drm_i915_private *i915)
 	ggtt_cleanup_hw(ggtt);
 }
 
+/**
+ * i915_ggtt_driver_late_release - Cleanup of GGTT that needs to be done after
+ * all free objects have been drained.
+ * @i915: i915 device
+ */
+void i915_ggtt_driver_late_release(struct drm_i915_private *i915)
+{
+	struct i915_ggtt *ggtt = &i915->ggtt;
+
+	GEM_WARN_ON(kref_read(&ggtt->vm.resv_ref) != 1);
+	dma_resv_fini(&ggtt->vm._resv);
+}
+
 static unsigned int gen6_get_total_gtt_size(u16 snb_gmch_ctl)
 {
 	snb_gmch_ctl >>= SNB_GMCH_GGMS_SHIFT;
@@ -828,6 +840,7 @@ static int ggtt_probe_common(struct i915_ggtt *ggtt, u64 size)
 		return -ENOMEM;
 	}
 
+	kref_init(&ggtt->vm.resv_ref);
 	ret = setup_scratch_page(&ggtt->vm);
 	if (ret) {
 		drm_err(&i915->drm, "Scratch setup failed\n");
@@ -1134,7 +1147,7 @@ static int ggtt_probe_hw(struct i915_ggtt *ggtt, struct intel_gt *gt)
 	ggtt->vm.gt = gt;
 	ggtt->vm.i915 = i915;
 	ggtt->vm.dma = i915->drm.dev;
-	dma_resv_init(&ggtt->vm.resv);
+	dma_resv_init(&ggtt->vm._resv);
 
 	if (INTEL_GEN(i915) <= 5)
 		ret = i915_gmch_probe(ggtt);
@@ -1143,7 +1156,7 @@ static int ggtt_probe_hw(struct i915_ggtt *ggtt, struct intel_gt *gt)
 	else
 		ret = gen8_gmch_probe(ggtt);
 	if (ret) {
-		dma_resv_fini(&ggtt->vm.resv);
+		dma_resv_fini(&ggtt->vm._resv);
 		return ret;
 	}