net/vdev_netvsc: fix device probing error flow

[ upstream commit 702b27d ]

If a device probe fails, the alarm is canceled and will no longer work
for previously probed devices.

Fix this by checking if alarm is necessary at the end of each device
probe.  Reset the alarm if there are vdev_netvsc_ctx created.

Fixes: e7dc5d7 ("net/vdev_netvsc: implement core functionality")

Signed-off-by: Long Li <longli@microsoft.com>
Acked-by: Matan Azrad <matan@nvidia.com>

drivers/net/vdev_netvsc/vdev_netvsc.c

@@ -673,6 +673,7 @@ vdev_netvsc_vdev_probe(struct rte_vdev_device *dev)
 	int ret;
 
 	DRV_LOG(DEBUG, "invoked as \"%s\", using arguments \"%s\"", name, args);
+	rte_eal_alarm_cancel(vdev_netvsc_alarm, NULL);
 	if (!kvargs) {
 		DRV_LOG(ERR, "cannot parse arguments list");
 		goto error;
@@ -688,17 +689,13 @@ vdev_netvsc_vdev_probe(struct rte_vdev_device *dev)
 			 !strcmp(pair->key, VDEV_NETVSC_ARG_MAC))
 			++specified;
 	}
-	if (ignore) {
-		if (kvargs)
-			rte_kvargs_free(kvargs);
-		return 0;
-	}
+	if (ignore)
+		goto ignore;
 	if (specified > 1) {
 		DRV_LOG(ERR, "More than one way used to specify the netvsc"
 			" device.");
 		goto error;
 	}
-	rte_eal_alarm_cancel(vdev_netvsc_alarm, NULL);
 	/* Gather interfaces. */
 	ret = vdev_netvsc_foreach_iface(vdev_netvsc_netvsc_probe, 1, name,
 					kvargs, specified, &matched);
@@ -719,17 +716,19 @@ vdev_netvsc_vdev_probe(struct rte_vdev_device *dev)
 		}
 		DRV_LOG(WARNING, "non-netvsc device was probed as netvsc");
 	}
-	ret = rte_eal_alarm_set(VDEV_NETVSC_PROBE_MS * 1000,
-				vdev_netvsc_alarm, NULL);
-	if (ret < 0) {
-		DRV_LOG(ERR, "unable to schedule alarm callback: %s",
-			rte_strerror(-ret));
-		goto error;
-	}
 error:
+	++vdev_netvsc_ctx_inst;
+ignore:
 	if (kvargs)
 		rte_kvargs_free(kvargs);
-	++vdev_netvsc_ctx_inst;
+	/* Reset alarm if there are device context created */
+	if (vdev_netvsc_ctx_count) {
+		ret = rte_eal_alarm_set(VDEV_NETVSC_PROBE_MS * 1000,
+					vdev_netvsc_alarm, NULL);
+		if (ret < 0)
+			DRV_LOG(ERR, "unable to schedule alarm callback: %s",
+				rte_strerror(-ret));
+	}
 	return 0;
 }