[dpdk-dev] [PATCH v1 2/3] net/ring: fix eth_dev device pointer on allocation

[Gaetan Rivet <grive@u256.net>]

When a net_ring device is allocated, its device pointer is not set
before calling rte_eth_dev_probing_finish, which is incorrect.

The following:
  commit: 96cb19521147 ("net/ring: use EAL APIs in PMD specific API")
  commit: a6992e961050 ("net/ring: set ethernet device field")

already attempted to fix this issue in 17.08, which was fine at the
time. Adding the hook rte_eth_dev_probing_finish() however created this
bug, as the eth_dev exposed when this hook is executed is expected to be
complete.

Remove the prior attempts to fix the issue in rte_pmd_ring_probe() and
write the pointer properly in do_eth_dev_ring_create().

Cc: stable@dpdk.org
Fixes: fbe90cdd776c ("ethdev: add probing finish function")
Cc: ferruh.yigit@intel.com
Cc: thomas@monjalon.net
Signed-off-by: Gaetan Rivet <grive@u256.net>
---
 drivers/net/ring/rte_eth_ring.c | 36 ++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ring/rte_eth_ring.c b/drivers/net/ring/rte_eth_ring.c
index 41acbc513..ad27f9d89 100644
--- a/drivers/net/ring/rte_eth_ring.c
+++ b/drivers/net/ring/rte_eth_ring.c
@@ -244,6 +244,26 @@ static const struct eth_dev_ops ops = {
 	.mac_addr_add = eth_mac_addr_add,
 };
 
+static int
+dev_name_cmp(const struct rte_device *dev, const void *_name)
+{
+	const char *name = _name;
+
+	return strcmp(dev->name, name);
+}
+
+static struct rte_device *
+ring_device_from_name(const char *name)
+{
+	struct rte_bus *vdev_bus;
+
+	vdev_bus = rte_bus_find_by_name("vdev");
+	if (vdev_bus == NULL)
+		return NULL;
+
+	return vdev_bus->find_device(NULL, dev_name_cmp, name);
+}
+
 static int
 do_eth_dev_ring_create(const char *name,
 		struct rte_ring * const rx_queues[],
@@ -294,6 +314,7 @@ do_eth_dev_ring_create(const char *name,
 	 * - store queue data in internals,
 	 * - store numa_node info in eth_dev_data
 	 * - point eth_dev_data to internals
+	 * - store EAL device in eth_dev,
 	 * - and point eth_dev structure to new eth_dev_data structure
 	 */
 
@@ -325,10 +346,17 @@ do_eth_dev_ring_create(const char *name,
 	data->kdrv = RTE_KDRV_NONE;
 	data->numa_node = numa_node;
 
-	/* finally assign rx and tx ops */
+	/* assign rx and tx ops */
 	eth_dev->rx_pkt_burst = eth_ring_rx;
 	eth_dev->tx_pkt_burst = eth_ring_tx;
 
+	/* finally set the rte_device pointer in eth_dev. */
+	eth_dev->device = ring_device_from_name(name);
+	if (eth_dev->device == NULL) {
+		rte_errno = ENODEV;
+		goto error;
+	}
+
 	rte_eth_dev_probing_finish(eth_dev);
 	*eth_dev_p = eth_dev;
 
@@ -584,9 +612,6 @@ rte_pmd_ring_probe(struct rte_vdev_device *dev)
 							  DEV_ATTACH, &eth_dev);
 			}
 
-			if (eth_dev)
-				eth_dev->device = &dev->device;
-
 			return ret;
 		}
 
@@ -644,9 +669,6 @@ rte_pmd_ring_probe(struct rte_vdev_device *dev)
 		}
 	}
 
-	if (eth_dev)
-		eth_dev->device = &dev->device;
-
 out_free:
 	rte_kvargs_free(kvlist);
 	rte_free(info);
-- 
2.26.2