drm/xe: Wrappers for setting and getting LRC references

There is a small but non-zero chance that VF post migration fixups
are running on an exec queue during teardown. The chances are
decreased by starting the teardown by releasing guc_id, but remain
non-zero. On the other hand the sync between fixups and EQ creation
(wait_valid_ggtt) drastically increases the chance for such parallel
teardown if queue creation error path is entered (err_lrc label).

The exec queue itself is not going to cause an issue, but LRCs have
a small chance of getting freed during the fixups.

Creating a setter and a getter makes it easier to protect the fixup
operations with a lock. For other driver activities, the original
access method (without any protection) can still be used.

v2: Separate lock, only for LRCs. Kerneldoc fixes. Subject tag fix.

Signed-off-by: Tomasz Lis <tomasz.lis@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patch.msgid.link/20260226212701.2937065-3-tomasz.lis@intel.com

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_exec_queue.h b/drivers/gpu/drm/xe/xe_exec_queue.h
index c9e3a7c2d249..a82d99bd77bc 100644
--- a/drivers/gpu/drm/xe/xe_exec_queue.h
+++ b/drivers/gpu/drm/xe/xe_exec_queue.h
@@ -160,6 +160,7 @@ void xe_exec_queue_update_run_ticks(struct xe_exec_queue *q);
 int xe_exec_queue_contexts_hwsp_rebase(struct xe_exec_queue *q, void *scratch);
 
 struct xe_lrc *xe_exec_queue_lrc(struct xe_exec_queue *q);
+struct xe_lrc *xe_exec_queue_get_lrc(struct xe_exec_queue *q, u16 idx);
 
 /**
  * xe_exec_queue_idle_skip_suspend() - Can exec queue skip suspend