Hi Reshma,

-----Original Message-----
From: Pattan, Reshma
Sent: Wednesday, September 28, 2016 4:04 PM
To: Kerlin, MarcinX <redacted>; dev@dpdk.org
Cc: De Lara Guarch, Pablo <redacted>;
thomas.monjalon@6wind.com; Kerlin, MarcinX [off-list ref]
Subject: RE: [dpdk-dev] [PATCH v4 1/2] librte_ether: add protection against
overwrite device data

quoted

-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Marcin Kerlin
Sent: Tuesday, September 27, 2016 12:13 PM
To: dev@dpdk.org
Cc: De Lara Guarch, Pablo <redacted>;
thomas.monjalon@6wind.com; Kerlin, MarcinX [off-list ref]
Subject: [dpdk-dev] [PATCH v4 1/2] librte_ether: add protection
against overwrite device data

+int
+rte_eth_dev_release_dev_data(uint8_t port_id) {
+	char device[RTE_ETH_NAME_MAX_LEN];
+	struct rte_eth_dev_data *eth_dev_data = NULL;
+
+

@@ -631,6 +691,8 @@ int
 rte_eth_dev_detach(uint8_t port_id, char *name)  {
 	struct rte_pci_addr addr;
+	struct rte_eth_dev_data *eth_dev_data = NULL;
+	char device[RTE_ETH_NAME_MAX_LEN];
 	int ret = -1;

 	if (name == NULL) {

@@ -642,6 +704,15 @@ rte_eth_dev_detach(uint8_t port_id, char *name)
 	if (rte_eth_dev_is_detachable(port_id))
 		goto err;

+	/* get device name by port id */
+	if (rte_eth_dev_get_name_by_port(port_id, device))
+		goto err;
+
+	/* look for an entry in the shared device data */
+	eth_dev_data = rte_eth_dev_get_dev_data_by_name(device);
+	if (eth_dev_data == NULL)
+		goto err;
+
 	if (rte_eth_dev_get_device_type(port_id) == RTE_ETH_DEV_PCI) {
 		ret = rte_eth_dev_get_addr_by_port(port_id, &addr);
 		if (ret < 0)

@@ -661,6 +732,9 @@ rte_eth_dev_detach(uint8_t port_id, char *name)
 			goto err;
 	}

+	/* clear an entry in the shared device data */
+	memset(eth_dev_data, 0, sizeof(struct rte_eth_dev_data));
+
 	return 0;

In this function, the new code chunks  together is nothing but the function "
rte_eth_dev_release_dev_data()".
So u can call the function itself rather than a duplicate code.

It was intentional, reason:

If I call function in place:
(1) beginning: then I lose device name for function below rte_eth_dev_detach_vdev (1.1):
	a) this is important for drivers  that hold name in shared rte_eth_dev_data[]
	b) not important for drivers that prepare own rte_eth_dev_data e.g pcap (rte_eth_pcap.c, line 816)

(2) end: then I lose device name for my function rte_eth_dev_release_dev_data, because in the above function 
rte_eth_dev_detach_vdev (1.1) for e.g pcap is call rte_free(eth_dev->data) which removes me a pointer to the
name (rte_eth_pcap.c, line 1079).


rte_eth_dev_detach (uint8_t port_id, char *name){
...
	(1) rte_eth_dev_release_dev_data(port_id);

	if (rte_eth_dev_get_device_type(port_id) == RTE_ETH_DEV_PCI) {
		ret = rte_eth_dev_get_addr_by_port(port_id, &addr);
		if (ret < 0)
			goto err;

		ret = rte_eth_dev_detach_pdev(port_id, &addr);
		if (ret < 0)
			goto err;

		snprintf(name, RTE_ETH_NAME_MAX_LEN,
			"%04x:%02x:%02x.%d",
			addr.domain, addr.bus,
			addr.devid, addr.function);
	} else {
		(1.1) ret = rte_eth_dev_detach_vdev(port_id, name);
		if (ret < 0)
			goto err;
	}

	(2) rte_eth_dev_release_dev_data(port_id);
...
}

This is reason why I keep name at the beginning but I release the name at the end function after detach.
At this point I do not see how the code directly replace by one function call.

Regards,
Marcin

Thanks,
Reshma