slimbus: messaging: check for valid transaction id

In some usecases transaction ids are dynamically allocated inside
the controller driver after sending the messages which have generic
acknowledge responses. So check for this before refcounting pm_runtime.

Without this we would end up imbalancing runtime pm count by
doing pm_runtime_put() in both slim_do_transfer() and slim_msg_response()
for a single pm_runtime_get() in slim_do_transfer()

Fixes: d3062a210930 ("slimbus: messaging: add slim_alloc/free_txn_tid()")
Cc: <[e-mail]>
Signed-off-by: Srinivas Kandagatla <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/slimbus/messaging.c

···
 			goto slim_xfer_err;
 		}
 	}
-
+	/* Initialize tid to invalid value */
+	txn->tid = 0;
 	need_tid = slim_tid_txn(txn->mt, txn->mc);
 
 	if (need_tid) {
···
 			txn->mt, txn->mc, txn->la, ret);
 
 slim_xfer_err:
-	if (!clk_pause_msg && (!need_tid  || ret == -ETIMEDOUT)) {
+	if (!clk_pause_msg && (txn->tid == 0  || ret == -ETIMEDOUT)) {
 		/*
 		 * remove runtime-pm vote if this was TX only, or
 		 * if there was error during this transaction