net: ipa: retry modem stop if busy

The IPA driver remove callback, ipa_remove(), calls ipa_modem_stop() if the setup stage of initialization is complete. If a concurrent call to ipa_modem_start() or ipa_modem_stop() has begin but not completed, ipa_modem_stop() can return an error (-EBUSY). The next patch adds a driver shutdown callback, which will simply call ipa_remove(). We really want our shutdown callback to clean things up. So add a single retry to the ipa_modem_stop() call in ipa_remove() after a short (millisecond) delay. This offers no guarantee the shutdown will complete successfully, but we'll at least try a little harder before giving up. Signed-off-by: Alex Elder <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]>
ambv · Nov 21, 2020 · 7c80e83 · 7c80e83
1 parent 1136145
commit 7c80e83
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/drivers/net/ipa/ipa_main.c b/drivers/net/ipa/ipa_main.c
@@ -863,6 +863,11 @@ static int ipa_remove(struct platform_device *pdev)
 
 	if (ipa->setup_complete) {
 		ret = ipa_modem_stop(ipa);
+		/* If starting or stopping is in progress, try once more */
+		if (ret == -EBUSY) {
+			usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
+			ret = ipa_modem_stop(ipa);
+		}
 		if (ret)
 			return ret;