[Intel-gfx] [PATCH v1] drm/i915: Fix a false alert of memory leak when free LRC

[yu.dai at intel.com]

From: Alex Dai <yu.dai at intel.com>

There is a memory leak warning message from i915_gem_context_clean
when GuC submission is enabled. The reason is that when LRC is
released, its ppgtt could be still referenced. The assumption that
all VMAs are unbound during release of LRC is not true.

v1: Move the code inside i915_gem_context_clean() to where ppgtt is
released because it is not cleaning context anyway but ppgtt.

Signed-off-by: Alex Dai <yu.dai at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 24 ------------------------
 drivers/gpu/drm/i915/i915_gem_gtt.c     | 12 ++++++++++++
 2 files changed, 12 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 204dc7c..cc5c8e6 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -133,23 +133,6 @@ static int get_context_size(struct drm_device *dev)
 	return ret;
 }
 
-static void i915_gem_context_clean(struct intel_context *ctx)
-{
-	struct i915_hw_ppgtt *ppgtt = ctx->ppgtt;
-	struct i915_vma *vma, *next;
-
-	if (!ppgtt)
-		return;
-
-	WARN_ON(!list_empty(&ppgtt->base.active_list));
-
-	list_for_each_entry_safe(vma, next, &ppgtt->base.inactive_list,
-				 mm_list) {
-		if (WARN_ON(__i915_vma_unbind_no_wait(vma)))
-			break;
-	}
-}
-
 void i915_gem_context_free(struct kref *ctx_ref)
 {
 	struct intel_context *ctx = container_of(ctx_ref, typeof(*ctx), ref);
@@ -159,13 +142,6 @@ void i915_gem_context_free(struct kref *ctx_ref)
 	if (i915.enable_execlists)
 		intel_lr_context_free(ctx);
 
-	/*
-	 * This context is going away and we need to remove all VMAs still
-	 * around. This is to handle imported shared objects for which
-	 * destructor did not run when their handles were closed.
-	 */
-	i915_gem_context_clean(ctx);
-
 	i915_ppgtt_put(ctx->ppgtt);
 
 	if (ctx->legacy_hw_ctx.rcs_state)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 016739e..d36943c 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2214,6 +2214,7 @@ void  i915_ppgtt_release(struct kref *kref)
 {
 	struct i915_hw_ppgtt *ppgtt =
 		container_of(kref, struct i915_hw_ppgtt, ref);
+	struct i915_vma *vma, *next;
 
 	trace_i915_ppgtt_release(&ppgtt->base);
 
@@ -2221,6 +2222,17 @@ void  i915_ppgtt_release(struct kref *kref)
 	WARN_ON(!list_empty(&ppgtt->base.active_list));
 	WARN_ON(!list_empty(&ppgtt->base.inactive_list));
 
+	/*
+	 * This ppgtt is going away and we need to remove all VMAs still
+	 * around. This is to handle imported shared objects for which
+	 * destructor did not run when their handles were closed.
+	 */
+	list_for_each_entry_safe(vma, next, &ppgtt->base.inactive_list,
+				 mm_list) {
+		if (WARN_ON(__i915_vma_unbind_no_wait(vma)))
+			break;
+	}
+
 	list_del(&ppgtt->base.global_link);
 	drm_mm_takedown(&ppgtt->base.mm);
 
-- 
2.5.0