[PATCH v3 2/2] net/tap: fix to populate fds in secondary process

[Kumara Parameshwaran <kumaraparamesh92@gmail.com>]

From: Kumara Parameshwaran <kparameshwar@vmware.com>

When a tap device is hotplugged to primary process which in turn
adds the device to all secondary process, the secondary process
does a tap_mp_attach_queues, but the fds are not populated in
the primary during the probe they are populated during the queue_setup,
added a fix to sync the queues during rte_eth_dev_start

Fixes: 4852aa8f6e21 ("drivers/net: enable hotplug on secondary process")
Cc: stable@dpdk.org

Signed-off-by: Kumara Parameshwaran <kparameshwar@vmware.com>
---
v3:
* Retain tap_sync_queues to retain the attach of secondary process
* Fix coding convention for a function definition
* Renamed rte_get_eth_dev_by_name to rte_eth_dev_get_by_name in sorted
  in version.map
* Remove uninteded blank line

 drivers/net/tap/rte_eth_tap.c | 80 +++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index f1b48cae82..d13baadbe7 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -67,6 +67,7 @@
 
 /* IPC key for queue fds sync */
 #define TAP_MP_KEY "tap_mp_sync_queues"
+#define TAP_MP_REQ_START_RXTX "tap_mp_req_start_rxtx"
 
 #define TAP_IOV_DEFAULT_MAX 1024
 
@@ -880,11 +881,49 @@ tap_link_set_up(struct rte_eth_dev *dev)
 	return tap_ioctl(pmd, SIOCSIFFLAGS, &ifr, 1, LOCAL_AND_REMOTE);
 }
 
+static int
+tap_mp_req_on_rxtx(struct rte_eth_dev *dev)
+{
+	struct rte_mp_msg msg;
+	struct ipc_queues *request_param = (struct ipc_queues *)msg.param;
+	int err;
+	int fd_iterator = 0;
+	struct pmd_process_private *process_private = dev->process_private;
+	int i;
+
+	memset(&msg, 0, sizeof(msg));
+	strlcpy(msg.name, TAP_MP_REQ_START_RXTX, sizeof(msg.name));
+	strlcpy(request_param->port_name, dev->data->name, sizeof(request_param->port_name));
+	msg.len_param = sizeof(*request_param);
+	for (i = 0; i < dev->data->nb_tx_queues; i++) {
+		msg.fds[fd_iterator++] = process_private->txq_fds[i];
+		msg.num_fds++;
+		request_param->txq_count++;
+	}
+	for (i = 0; i < dev->data->nb_rx_queues; i++) {
+		msg.fds[fd_iterator++] = process_private->rxq_fds[i];
+		msg.num_fds++;
+		request_param->rxq_count++;
+	}
+
+	err = rte_mp_sendmsg(&msg);
+	if (err < 0) {
+		TAP_LOG(ERR, "Failed to send start req to secondary %d",
+			rte_errno);
+		return -1;
+	}
+
+	return 0;
+}
+
 static int
 tap_dev_start(struct rte_eth_dev *dev)
 {
 	int err, i;
 
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
+		tap_mp_req_on_rxtx(dev);
+
 	err = tap_intr_handle_set(dev, 1);
 	if (err)
 		return err;
@@ -901,6 +940,34 @@ tap_dev_start(struct rte_eth_dev *dev)
 	return err;
 }
 
+static int
+tap_mp_req_start_rxtx(const struct rte_mp_msg *request, __rte_unused const void *peer)
+{
+	struct rte_eth_dev *dev;
+	const struct ipc_queues *request_param =
+		(const struct ipc_queues *)request->param;
+	int fd_iterator;
+	int queue;
+	struct pmd_process_private *process_private;
+
+	dev = rte_eth_dev_get_by_name(request_param->port_name);
+	if (!dev) {
+		TAP_LOG(ERR, "Failed to get dev for %s",
+			request_param->port_name);
+		return -1;
+	}
+	process_private = dev->process_private;
+	fd_iterator = 0;
+	TAP_LOG(DEBUG, "tap_attach rx_q:%d tx_q:%d\n", request_param->rxq_count,
+		request_param->txq_count);
+	for (queue = 0; queue < request_param->txq_count; queue++)
+		process_private->txq_fds[queue] = request->fds[fd_iterator++];
+	for (queue = 0; queue < request_param->rxq_count; queue++)
+		process_private->rxq_fds[queue] = request->fds[fd_iterator++];
+
+	return 0;
+}
+
 /* This function gets called when the current port gets stopped.
  */
 static int
@@ -1084,6 +1151,9 @@ tap_dev_close(struct rte_eth_dev *dev)
 
 	if (rte_eal_process_type() != RTE_PROC_PRIMARY) {
 		rte_free(dev->process_private);
+		if (tap_devices_count == 1)
+			rte_mp_action_unregister(TAP_MP_REQ_START_RXTX);
+		tap_devices_count--;
 		return 0;
 	}
 
@@ -2445,6 +2515,16 @@ rte_pmd_tap_probe(struct rte_vdev_device *dev)
 		ret = tap_mp_attach_queues(name, eth_dev);
 		if (ret != 0)
 			return -1;
+
+		if (!tap_devices_count) {
+			ret = rte_mp_action_register(TAP_MP_REQ_START_RXTX, tap_mp_req_start_rxtx);
+			if (ret < 0 && rte_errno != ENOTSUP) {
+				TAP_LOG(ERR, "tap: Failed to register IPC callback: %s",
+					strerror(rte_errno));
+				return -1;
+			}
+		}
+		tap_devices_count++;
 		rte_eth_dev_probing_finish(eth_dev);
 		return 0;
 	}
-- 
2.17.1