[PATCH v4 1/8] vdev: implement plug operation

[Gaetan Rivet <gaetan.rivet@6wind.com>]

This method must be implemented to allow using a unified, generic API to
hotplug devices, including virtual ones.

VDEV devices actually exist unattached after performing a scan on the
rte_devargs list. As such it makes sense to be able to perform a device
hotplug afterward.

Finally, missing this generic interface forces the EAL to be dependent
on vdev-specific API, which hinders the plan of moving the vdev bus to
drivers/bus.

Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
---
 lib/librte_eal/common/eal_common_vdev.c  | 12 +++++++-----
 lib/librte_eal/common/include/rte_vdev.h |  7 +++++++
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/lib/librte_eal/common/eal_common_vdev.c b/lib/librte_eal/common/eal_common_vdev.c
index e00dda9..85cf3fc 100644
--- a/lib/librte_eal/common/eal_common_vdev.c
+++ b/lib/librte_eal/common/eal_common_vdev.c
@@ -319,12 +319,14 @@ vdev_find_device(const struct rte_device *start, rte_dev_cmp_t cmp,
 }
 
 static int
+vdev_plug(struct rte_device *dev, const char *args __rte_unused)
+{
+	return vdev_probe_all_drivers(RTE_DEV_TO_VDEV(dev));
+}
+
+static int
 vdev_unplug(struct rte_device *dev)
 {
-	/*
-	 * The virtual bus doesn't support 'unattached' devices so this is
-	 * actually equal to hotplugging removal of it.
-	 */
 	return rte_vdev_uninit(dev->name);
 }
 
@@ -332,7 +334,7 @@ static struct rte_bus rte_vdev_bus = {
 	.scan = vdev_scan,
 	.probe = vdev_probe,
 	.find_device = vdev_find_device,
-	/* .plug = NULL, see comment on vdev_unplug */
+	.plug = vdev_plug,
 	.unplug = vdev_unplug,
 	.parse = vdev_parse,
 };
diff --git a/lib/librte_eal/common/include/rte_vdev.h b/lib/librte_eal/common/include/rte_vdev.h
index fc24298..29f5a52 100644
--- a/lib/librte_eal/common/include/rte_vdev.h
+++ b/lib/librte_eal/common/include/rte_vdev.h
@@ -46,6 +46,13 @@ struct rte_vdev_device {
 	struct rte_device device;               /**< Inherit core device */
 };
 
+/**
+ * @internal
+ * Helper macro for drivers that need to convert to struct rte_vdev_device.
+ */
+#define RTE_DEV_TO_VDEV(ptr) \
+	container_of(ptr, struct rte_vdev_device, device)
+
 static inline const char *
 rte_vdev_device_name(const struct rte_vdev_device *dev)
 {
-- 
2.1.4