drm/xe/guc: Fix resource leak in xe_guc_ct_init_noalloc()

xe_guc_ct_init_noalloc() allocates the CT workqueue and other helpers
before it tries to initialize ct->lock. If drmm_mutex_init() fails
we currently bail out without releasing those resources because the
guc_ct_fini() hasn’t been registered yet.

Since destroy_workqueue() in guc_ct_fini() may flush the workqueue, which
in turn can take the ct lock, the initialization sequence is restructured
to first initialize the ct->lock, then set up all CT state, and finally
register guc_ct_fini().

v2: guc_ct_fini() does take ct lock. (Matt)
v3: move primelockdep() together with drmm_mutex_init(). (Lucas)

Fixes: dd08ebf ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: Lucas De Marchi <[email protected]>
Cc: Matthew Brost <[email protected]>
Signed-off-by: Shuicheng Lin <[email protected]>
Reviewed-by: Lucas De Marchi <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Lucas De Marchi <[email protected]>
(cherry picked from commit 2e4ad5b)
Signed-off-by: Lucas De Marchi <[email protected]>

Author: ShuichengLin

drivers/gpu/drm/xe/xe_guc_ct.c

@@ -226,6 +226,12 @@ int xe_guc_ct_init_noalloc(struct xe_guc_ct *ct)
 
 	xe_gt_assert(gt, !(guc_ct_size() % PAGE_SIZE));
 
+	err = drmm_mutex_init(&xe->drm, &ct->lock);
+	if (err)
+		return err;
+
+	primelockdep(ct);
+
 	ct->g2h_wq = alloc_ordered_workqueue("xe-g2h-wq", WQ_MEM_RECLAIM);
 	if (!ct->g2h_wq)
 		return -ENOMEM;
@@ -241,12 +247,6 @@ int xe_guc_ct_init_noalloc(struct xe_guc_ct *ct)
 	init_waitqueue_head(&ct->wq);
 	init_waitqueue_head(&ct->g2h_fence_wq);
 
-	err = drmm_mutex_init(&xe->drm, &ct->lock);
-	if (err)
-		return err;
-
-	primelockdep(ct);
-
 	err = drmm_add_action_or_reset(&xe->drm, guc_ct_fini, ct);
 	if (err)
 		return err;