[dpdk-dev] [PATCH v5 02/24] bus/vdev: enable one device scan

[Qi Zhang]

The patch implements the ops scan_one for the vdev bus, which gives two
benefits:
1. Improves scan efficiency when a device is attached as hotplug, since
there is no need to populate a new device by iterating all devargs in
devargs_list
2. It also avoids sync IPC invoke (which happens in vdev->scan on
secondary process). The benefit is this removes the potential deadlock
in the case when a secondary process receives a request from primary
process to attach a new device, since vdev->scan will be invoked on mp
thread itself in that case

Signed-off-by: Qi Zhang <qi.z.zhang at intel.com>
Acked-by: Remy Horton <remy.horton at intel.com>
---
 drivers/bus/vdev/vdev.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c
index 6139dd551..cdbd77df0 100644
--- a/drivers/bus/vdev/vdev.c
+++ b/drivers/bus/vdev/vdev.c
@@ -467,6 +467,35 @@ vdev_scan(void)
 	return 0;
 }
 
+static struct rte_device *vdev_scan_one(struct rte_devargs *devargs)
+{
+	struct rte_vdev_device *dev = NULL;
+
+	dev = calloc(1, sizeof(*dev));
+	if (!dev) {
+		VDEV_LOG(ERR, "failed to allocate memory for new device");
+		return NULL;
+	}
+
+	rte_spinlock_recursive_lock(&vdev_device_list_lock);
+
+	if (find_vdev(devargs->name)) {
+		VDEV_LOG(ERR, "device %s already exist", devargs->name);
+		free(dev);
+		rte_spinlock_recursive_unlock(&vdev_device_list_lock);
+		return NULL;
+	}
+
+	dev->device.devargs = devargs;
+	dev->device.numa_node = SOCKET_ID_ANY;
+	dev->device.name = devargs->name;
+	TAILQ_INSERT_TAIL(&vdev_device_list, dev, next);
+
+	rte_spinlock_recursive_unlock(&vdev_device_list_lock);
+
+	return &dev->device;
+}
+
 static int
 vdev_probe(void)
 {
@@ -531,6 +560,7 @@ vdev_unplug(struct rte_device *dev)
 
 static struct rte_bus rte_vdev_bus = {
 	.scan = vdev_scan,
+	.scan_one = vdev_scan_one,
 	.probe = vdev_probe,
 	.find_device = vdev_find_device,
 	.plug = vdev_plug,
-- 
2.13.6