drm/xe: Add helper function to inject fault into ct_dead_capture()

When injecting fault to xe_guc_ct_send_recv() & xe_guc_mmio_send_recv()
functions, the CI test systems are going out of space and crashing. To
avoid this issue, a new helper function is created and when fault is
injected into this xe_should_fail_ct_dead_capture() helper function,
ct dead capture is avoided which suppresses ct dumps in the log.

Signed-off-by: Satyanarayana K V P <[email protected]>
Suggested-by: John Harrison <[email protected]>
Tested-by: Aditya Chauhan <[email protected]>

Author: ksatya-dev

drivers/gpu/drm/xe/xe_guc_ct.c

@@ -1769,6 +1769,20 @@ void xe_guc_ct_print(struct xe_guc_ct *ct, struct drm_printer *p, bool want_ctb)
 }
 
 #if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
+/**
+ * xe_should_fail_ct_dead_capture - Helper function to inject fault.
+ *
+ * This is a helper function to inject fault into ct_dead_capture().
+ * As fault is injected using this function, need to make sure that
+ * the compiler does not optimize and make it as a inline function.
+ * To prevent compile optimization, "noinline" is added.
+ */
+static noinline int xe_should_fail_ct_dead_capture(void)
+{
+	return 0;
+}
+ALLOW_ERROR_INJECTION(xe_should_fail_ct_dead_capture, ERRNO);
+
 static void ct_dead_capture(struct xe_guc_ct *ct, struct guc_ctb *ctb, u32 reason_code)
 {
 	struct xe_guc_log_snapshot *snapshot_log;
@@ -1777,6 +1791,13 @@ static void ct_dead_capture(struct xe_guc_ct *ct, struct guc_ctb *ctb, u32 reaso
 	unsigned long flags;
 	bool have_capture;
 
+	/*
+	 * Huge dump is getting generated when injecting error for guc CT/MMIO
+	 * functions. So, let us suppress the dump when fault is injected.
+	 */
+	if (xe_should_fail_ct_dead_capture())
+		return;
+
 	if (ctb)
 		ctb->info.broken = true;