[PATCH v3 1/4] drm/xe/queue: Call fini on exec queue creation fail

[Tomasz Lis <tomasz.lis@intel.com>]

Every call to queue init should have a corresponding fini call.
Skipping this would mean skipping removal of the queue from GuC list
(which is part of guc_id allocation). A damaged queue stored in
exec_queue_lookup list would lead to invalid memory reference,
sooner or later.

Call fini to free guc_id. This must be done before any internal
LRCs are freed.

Since the finalization with this extra call became very similar to
__xe_exec_queue_fini(), reuse that. To make this reuse possible,
alter xe_lrc_put() so it can survive NULL parameters, like other
similar functions.

v2: Reuse _xe_exec_queue_fini(). Make xe_lrc_put() aware of NULLs.

Fixes: 3c1fa4aa60b1 ("drm/xe: Move queue init before LRC creation")
Signed-off-by: Tomasz Lis <tomasz.lis@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com> (v1)
---
 drivers/gpu/drm/xe/xe_exec_queue.c | 23 +++++++++++------------
 drivers/gpu/drm/xe/xe_lrc.h        |  3 ++-
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c b/drivers/gpu/drm/xe/xe_exec_queue.c
index f8980cb7293d..b4ef725a682d 100644
--- a/drivers/gpu/drm/xe/xe_exec_queue.c
+++ b/drivers/gpu/drm/xe/xe_exec_queue.c
@@ -270,6 +270,16 @@ static struct xe_exec_queue *__xe_exec_queue_alloc(struct xe_device *xe,
 	return q;
 }
 
+static void __xe_exec_queue_fini(struct xe_exec_queue *q)
+{
+	int i;
+
+	q->ops->fini(q);
+
+	for (i = 0; i < q->width; ++i)
+		xe_lrc_put(q->lrc[i]);
+}
+
 static int __xe_exec_queue_init(struct xe_exec_queue *q, u32 exec_queue_flags)
 {
 	int i, err;
@@ -324,21 +334,10 @@ static int __xe_exec_queue_init(struct xe_exec_queue *q, u32 exec_queue_flags)
 	return 0;
 
 err_lrc:
-	for (i = i - 1; i >= 0; --i)
-		xe_lrc_put(q->lrc[i]);
+	__xe_exec_queue_fini(q);
 	return err;
 }
 
-static void __xe_exec_queue_fini(struct xe_exec_queue *q)
-{
-	int i;
-
-	q->ops->fini(q);
-
-	for (i = 0; i < q->width; ++i)
-		xe_lrc_put(q->lrc[i]);
-}
-
 struct xe_exec_queue *xe_exec_queue_create(struct xe_device *xe, struct xe_vm *vm,
 					   u32 logical_mask, u16 width,
 					   struct xe_hw_engine *hwe, u32 flags,
diff --git a/drivers/gpu/drm/xe/xe_lrc.h b/drivers/gpu/drm/xe/xe_lrc.h
index 3e500004f1ae..48f7c26cf129 100644
--- a/drivers/gpu/drm/xe/xe_lrc.h
+++ b/drivers/gpu/drm/xe/xe_lrc.h
@@ -75,7 +75,8 @@ static inline struct xe_lrc *xe_lrc_get(struct xe_lrc *lrc)
  */
 static inline void xe_lrc_put(struct xe_lrc *lrc)
 {
-	kref_put(&lrc->refcount, xe_lrc_destroy);
+	if (lrc)
+		kref_put(&lrc->refcount, xe_lrc_destroy);
 }
 
 /**
-- 
2.25.1