[dpdk-dev] [PATCH v2 4/6] net/tap: fix multi-queue support

[Wiles, Keith]

> On Feb 6, 2017, at 9:45 AM, Pascal Mazon <pascal.mazon at 6wind.com> wrote:
> 
> On Sun,  5 Feb 2017 10:05:07 -0600
> Keith Wiles <keith.wiles at intel.com> wrote:
> 
>> At the same time remove the code which created the first device queue
>> at probe time. Now all queues are created during queue setup calls.
>> 
>> Signed-off-by: Keith Wiles <keith.wiles at intel.com>
>> ---
>> drivers/net/tap/rte_eth_tap.c | 104
>> ++++++++++++++---------------------------- 1 file changed, 34 insertions(+),
>> 70 deletions(-)
>> 
>> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
>> index 61659bc..7c923a2 100644
>> --- a/drivers/net/tap/rte_eth_tap.c
>> +++ b/drivers/net/tap/rte_eth_tap.c
>> @@ -57,7 +57,11 @@
>> #define ETH_TAP_IFACE_ARG       "iface"
>> #define ETH_TAP_SPEED_ARG       "speed"
>> 
>> +#ifdef IFF_MULTI_QUEUE
>> #define RTE_PMD_TAP_MAX_QUEUES	16
>> +#else
>> +#define RTE_PMD_TAP_MAX_QUEUES	1
>> +#endif
>> 
>> static struct rte_vdev_driver pmd_tap_drv;
>> 
>> @@ -114,17 +118,20 @@ struct pmd_internals {
>>  * supplied name.
>>  */
>> static int
>> -tun_alloc(char *name)
>> +tun_alloc(struct pmd_internals *pmd, uint16_t qid)
>> {
>> 	struct ifreq ifr;
>> +#ifdef IFF_MULTI_QUEUE
>> 	unsigned int features;
>> +#endif
>> 	int fd;
>> 
>> 	memset(&ifr, 0, sizeof(struct ifreq));
>> 
>> 	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
>> -	if (name && name[0])
>> -		strncpy(ifr.ifr_name, name, IFNAMSIZ);
>> +	strncpy(ifr.ifr_name, pmd->name, IFNAMSIZ);
>> +
>> +	RTE_LOG(DEBUG, PMD, "ifr_name '%s'\n", ifr.ifr_name);
>> 
>> 	fd = open(TUN_TAP_DEV_PATH, O_RDWR);
>> 	if (fd < 0) {
>> @@ -132,37 +139,26 @@ tun_alloc(char *name)
>> 		goto error;
>> 	}
>> 
>> -	/* Grab the TUN features to verify we can work */
>> +#ifdef IFF_MULTI_QUEUE
>> +	/* Grab the TUN features to verify we can work multi-queue */
>> 	if (ioctl(fd, TUNGETFEATURES, &features) < 0) {
>> -		RTE_LOG(ERR, PMD, "Unable to get TUN/TAP features\n");
>> +		RTE_LOG(ERR, PMD, "TAP unable to get TUN/TAP features\n");
>> 		goto error;
>> 	}
>> -	RTE_LOG(DEBUG, PMD, "TUN/TAP Features %08x\n", features);
>> +	RTE_LOG(DEBUG, PMD, "  TAP Features %08x\n", features);
>> 
>> -#ifdef IFF_MULTI_QUEUE
>> -	if (!(features & IFF_MULTI_QUEUE) && (RTE_PMD_TAP_MAX_QUEUES > 1)) {
>> -		RTE_LOG(DEBUG, PMD, "TUN/TAP device only one queue\n");
>> -		goto error;
>> -	} else if ((features & IFF_ONE_QUEUE) &&
>> -			(RTE_PMD_TAP_MAX_QUEUES == 1)) {
>> -		ifr.ifr_flags |= IFF_ONE_QUEUE;
>> -		RTE_LOG(DEBUG, PMD, "Single queue only support\n");
>> -	} else {
>> -		ifr.ifr_flags |= IFF_MULTI_QUEUE;
>> -		RTE_LOG(DEBUG, PMD, "Multi-queue support for %d queues\n",
>> +	if (features & IFF_MULTI_QUEUE) {
>> +		RTE_LOG(DEBUG, PMD, "  Multi-queue support for %d queues\n",
>> 			RTE_PMD_TAP_MAX_QUEUES);
>> -	}
>> -#else
>> -	if (RTE_PMD_TAP_MAX_QUEUES > 1) {
>> -		RTE_LOG(DEBUG, PMD, "TUN/TAP device only one queue\n");
>> -		goto error;
>> -	} else {
>> +		ifr.ifr_flags |= IFF_MULTI_QUEUE;
>> +	} else
>> +#endif
>> +	{
>> 		ifr.ifr_flags |= IFF_ONE_QUEUE;
>> 		RTE_LOG(DEBUG, PMD, "Single queue only support\n");
>> 	}
>> -#endif
>> 
>> -	/* Set the TUN/TAP configuration and get the name if needed */
>> +	/* Set the TUN/TAP configuration and set the name if needed */
>> 	if (ioctl(fd, TUNSETIFF, (void *)&ifr) < 0) {
>> 		RTE_LOG(ERR, PMD, "Unable to set TUNSETIFF for %s\n",
>> 			ifr.ifr_name);
>> @@ -177,9 +173,15 @@ tun_alloc(char *name)
>> 		goto error;
>> 	}
>> 
>> -	/* If the name is different that new name as default */
>> -	if (name && strcmp(name, ifr.ifr_name))
>> -		snprintf(name, RTE_ETH_NAME_MAX_LEN - 1, "%s", ifr.ifr_name);
>> +	if (qid == 0) {
>> +		if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
>> +			RTE_LOG(ERR, PMD, "ioctl failed (SIOCGIFHWADDR)
>> (%s)\n",
>> +				ifr.ifr_name);
>> +			goto error;
>> +		}
>> +
>> +		rte_memcpy(&pmd->eth_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
>> +	}
>> 
>> 	return fd;
>> 
>> @@ -507,7 +509,7 @@ tap_setup_queue(struct rte_eth_dev *dev,
>> 		if (fd < 0) {
>> 			RTE_LOG(INFO, PMD, "Add queue to TAP %s for qid
>> %d\n", pmd->name, qid);
>> -			fd = tun_alloc(pmd->name);
>> +			fd = tun_alloc(pmd, qid);
>> 			if (fd < 0) {
>> 				RTE_LOG(ERR, PMD, "tun_alloc(%s) failed\n",
>> 					pmd->name);
>> @@ -629,34 +631,13 @@ static const struct eth_dev_ops ops = {
>> };
>> 
>> static int
>> -pmd_mac_address(int fd, struct ether_addr *addr)
>> -{
>> -	struct ifreq ifr;
>> -
>> -	if ((fd <= 0) || !addr)
>> -		return -1;
>> -
>> -	memset(&ifr, 0, sizeof(ifr));
>> -
>> -	if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
>> -		RTE_LOG(ERR, PMD, "ioctl failed (SIOCGIFHWADDR) (%s)\n",
>> -			ifr.ifr_name);
>> -		return -1;
>> -	}
>> -
>> -	rte_memcpy(addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
>> -
>> -	return 0;
>> -}
>> -
>> -static int
>> eth_dev_tap_create(const char *name, char *tap_name)
>> {
>> 	int numa_node = rte_socket_id();
>> 	struct rte_eth_dev *dev = NULL;
>> 	struct pmd_internals *pmd = NULL;
>> 	struct rte_eth_dev_data *data = NULL;
>> -	int i, fd = -1;
>> +	int i;
>> 
>> 	RTE_LOG(INFO, PMD,
>> 		"%s: Create TAP Ethernet device with %d queues on numa %u\n",
>> @@ -674,7 +655,6 @@ eth_dev_tap_create(const char *name, char *tap_name)
>> 		goto error_exit;
>> 	}
>> 
>> -	/* Use the name and not the tap_name */
>> 	dev = rte_eth_dev_allocate(tap_name);
>> 	if (!dev) {
>> 		RTE_LOG(ERR, PMD, "Unable to allocate device struct\n");
>> @@ -705,28 +685,12 @@ eth_dev_tap_create(const char *name, char *tap_name)
>> 	dev->tx_pkt_burst = pmd_tx_burst;
>> 	snprintf(dev->data->name, sizeof(dev->data->name), "%s", name);
>> 
>> -	/* Create the first Tap device */
>> -	fd = tun_alloc(tap_name);
>> -	if (fd < 0) {
>> -		RTE_LOG(ERR, PMD, "tun_alloc() failed\n");
>> -		goto error_exit;
>> -	}
>> -
>> -	/* Presetup the fds to -1 as being not working */
>> -	for (i = 1; i < RTE_PMD_TAP_MAX_QUEUES; i++) {
>> +	/* Presetup the fds to -1 as being not valid */
>> +	for (i = 0; i < RTE_PMD_TAP_MAX_QUEUES; i++) {
>> 		pmd->rxq[i].fd = -1;
>> 		pmd->txq[i].fd = -1;
>> 	}
>> 
>> -	/* Take the TUN/TAP fd and place in the first location */
>> -	pmd->rxq[0].fd = fd;
>> -	pmd->txq[0].fd = fd;
>> -
>> -	if (pmd_mac_address(fd, &pmd->eth_addr) < 0) {
>> -		RTE_LOG(ERR, PMD, "Unable to get MAC address\n");
>> -		goto error_exit;
>> -	}
>> -
>> 	return 0;
>> 
>> error_exit:
> 
> I like that you use #ifdef IFF_MULTI_QUEUE, it's a good thing.
> 
> Something bothers me, though.
> I don't think you should close all fds in the dev_stop() function, but
> rather in the dev_close() function.
> After a dev_close(), we don't expect the user to re-use the device, so
> we can safely remove the queues. However, after a dev_stop(), the user
> can definitely do a dev_start(), which in your case would fail because
> it will try to set the link up on an inexisting device.
> 
> dev_stop() should act as dev_start(), in symmetry, and dev_close()
> should close the fd/queues.

That is a good point should I create v3 or do a patch for that after this release?

> 
> The rest of the code looks OK to me.
> 
> Best regards,
> Pascal

Regards,
Keith