[PATCH v5 3/4] drm/amdgpu/aca: Fix inverted validation logic and list cleanup

[Sreeraj S Kurup]

"aca_handle_is_valid()" used inverted list-membership logic. It
returned false when "!list_empty(&handle->node)" was true, even though
a non-empty node indicates that the handle is currently registered. As
a result, registered handles were incorrectly considered invalid.

Fix "aca_handle_is_valid()" to verify that the handle is non-NULL, has a
valid mask, and is currently registered in the handle list.

Update "amdgpu_aca_get_error_data()" to reject invalid handles and
return 0 rather than "-EOPNOTSUPP". This allows global RAS queries to
safely skip non-ACA blocks without treating an unsupported block as an
error.

Additionally, use "list_del_init()" in "remove_aca_handle()" before
"aca_fini_error_cache()". Unlike "list_del()", which poisons the
removed node's pointers, "list_del_init()" reinitializes the node as an
empty list. This ensures that "aca_handle_is_valid()" recognizes the
handle as unregistered before its error cache is destroyed.

Signed-off-by: Sreeraj S Kurup <sreekuttan2156239@xxxxxxxxx>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c
index c76664af9902..d48f2c4d6c84 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c
@@ -586,10 +586,7 @@ static int __aca_get_error_data(struct amdgpu_device *adev, struct aca_handle *h
 
 static bool aca_handle_is_valid(struct aca_handle *handle)
 {
-	if (!handle->mask || !list_empty(&handle->node))
-		return false;
-
-	return true;
+	return handle && handle->mask && !list_empty(&handle->node);
 }
 
 int amdgpu_aca_get_error_data(struct amdgpu_device *adev, struct aca_handle *handle,
@@ -599,8 +596,8 @@ int amdgpu_aca_get_error_data(struct amdgpu_device *adev, struct aca_handle *han
 	if (!handle || !err_data)
 		return -EINVAL;
 
-	if (aca_handle_is_valid(handle))
-		return -EOPNOTSUPP;
+	if (!aca_handle_is_valid(handle))
+		return 0;
 
 	if ((type < 0) || (!(BIT(type) & handle->mask)))
 		return  0;
@@ -716,9 +713,10 @@ static void remove_aca_handle(struct aca_handle *handle)
 {
 	struct aca_handle_manager *mgr = handle->mgr;
 
-	aca_fini_error_cache(handle);
-	list_del(&handle->node);
+	list_del_init(&handle->node);
 	mgr->nr_handles--;
+	aca_fini_error_cache(handle);
+
 }
 
 static void remove_aca_sysfs(struct aca_handle *handle)
-- 
2.54.0