[PATCH v3] drm/xe/xe_guc_ct: Exit CT submission fence wait on GT reset

[Jonathan Cavitt <jonathan.cavitt@intel.com>]

It's possible if unlikely that the GuC could be reset in the time
between performing a guc_ct_send and the G2H fence completing in
guc_ct_send_recv.  Exit early if this is occurs.

v2: Rebase

v3: goto retry_same_fence if ct is not alive (Stuart)

Suggested-by: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
---
 drivers/gpu/drm/xe/xe_guc_ct.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
index dfbf76037b04..0bdcbe6503a7 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct.c
+++ b/drivers/gpu/drm/xe/xe_guc_ct.c
@@ -1238,6 +1238,10 @@ int xe_guc_ct_send_g2h_handler(struct xe_guc_ct *ct, const u32 *action, u32 len)
 	return ret;
 }
 
+#define ct_alive(ct)    \
+	(xe_guc_ct_enabled(ct) && !ct->ctbs.h2g.info.broken && \
+	 !ct->ctbs.g2h.info.broken)
+
 /*
  * Check if a GT reset is in progress or will occur and if GT reset brought the
  * CT back up. Randomly picking 5 seconds for an upper limit to do a GT a reset.
@@ -1247,12 +1251,8 @@ static bool retry_failure(struct xe_guc_ct *ct, int ret)
 	if (!(ret == -EDEADLK || ret == -EPIPE || ret == -ENODEV))
 		return false;
 
-#define ct_alive(ct)	\
-	(xe_guc_ct_enabled(ct) && !ct->ctbs.h2g.info.broken && \
-	 !ct->ctbs.g2h.info.broken)
 	if (!wait_event_interruptible_timeout(ct->wq, ct_alive(ct), HZ * 5))
 		return false;
-#undef ct_alive
 
 	return true;
 }
@@ -1304,7 +1304,11 @@ static int guc_ct_send_recv(struct xe_guc_ct *ct, const u32 *action, u32 len,
 	/* READ_ONCEs pairs with WRITE_ONCEs in parse_g2h_response
 	 * and g2h_fence_cancel.
 	 */
-	ret = wait_event_timeout(ct->g2h_fence_wq, READ_ONCE(g2h_fence.done), HZ);
+	ret = wait_event_timeout(ct->g2h_fence_wq, !ct_alive(ct) ||
+				 READ_ONCE(g2h_fence.done), HZ);
+	if (!ct_alive(ct))
+		goto retry_same_fence;
+
 	if (!ret) {
 		LNL_FLUSH_WORK(&ct->g2h_worker);
 		if (READ_ONCE(g2h_fence.done)) {
-- 
2.43.0