[dpdk-dev] [PATCH 2/5] net/tap: fix multi-queue support

Wiles, Keith keith.wiles at intel.com
Fri Feb 3 21:32:33 CET 2017


> On Feb 3, 2017, at 3:37 AM, Pascal Mazon <pascal.mazon at 6wind.com> wrote:
> 
> On Thu,  2 Feb 2017 16:33:27 -0600
> Keith Wiles <keith.wiles at intel.com> wrote:
> 
>> Signed-off-by: Keith Wiles <keith.wiles at intel.com>
>> ---
>> drivers/net/tap/rte_eth_tap.c | 93
>> ++++++++++++++++++++++--------------------- 1 file changed, 48 insertions(+),
>> 45 deletions(-)
>> 
>> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
>> index 3f179c3..9ed7a87 100644
>> --- a/drivers/net/tap/rte_eth_tap.c
>> +++ b/drivers/net/tap/rte_eth_tap.c
>> @@ -115,10 +115,9 @@ struct pmd_internals {
>>  * supplied name.
>>  */
>> static int
>> -tun_alloc(char *name)
>> +tun_alloc(char *name, uint16_t qid)
>> {
>> 	struct ifreq ifr;
>> -	unsigned int features;
>> 	int fd;
>> 
>> 	memset(&ifr, 0, sizeof(struct ifreq));
>> @@ -133,55 +132,57 @@ tun_alloc(char *name)
>> 		goto error;
>> 	}
>> 
>> -	/* Grab the TUN features to verify we can work */
>> -	if (ioctl(fd, TUNGETFEATURES, &features) < 0) {
>> -		RTE_LOG(ERR, PMD, "Unable to get TUN/TAP features\n");
>> -		goto error;
>> -	}
>> -	RTE_LOG(DEBUG, PMD, "TUN/TAP Features %08x\n", features);
>> +	/* This can only be done once per interface */
>> +	if (qid == 0) {
>> +		unsigned int features;
>> +
>> +		/* Grab the TUN features to verify we can work */
>> +		if (ioctl(fd, TUNGETFEATURES, &features) < 0) {
>> +			RTE_LOG(ERR, PMD, "Unable to get TUN/TAP
>> features\n");
>> +			goto error;
>> +		}
>> +		RTE_LOG(DEBUG, PMD, "TUN/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",
>> -			RTE_PMD_TAP_MAX_QUEUES);
>> -	}
>> +		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",
>> +				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_ONE_QUEUE;
>> -		RTE_LOG(DEBUG, PMD, "Single queue only support\n");
>> -	}
>> +		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_ONE_QUEUE;
>> +			RTE_LOG(DEBUG, PMD, "Single queue only support\n");
>> +		}
>> #endif
>> 
>> -	/* Set the TUN/TAP configuration and get 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);
>> -		perror("TUNSETIFF");
>> -		goto error;
>> -	}
>> +		/* Set the TUN/TAP configuration and get 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);
>> +			perror("TUNSETIFF");
>> +			goto error;
>> +		}
>> 
>> -	/* Always set the file descriptor to non-blocking */
>> -	if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
>> -		RTE_LOG(ERR, PMD, "Unable to set to nonblocking\n");
>> -		perror("F_SETFL, NONBLOCK");
>> -		goto error;
>> +		/* Always set the file descriptor to non-blocking */
>> +		if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
>> +			RTE_LOG(WARNING, PMD, "Unable to set %s to
>> nonblocking\n",
>> +				ifr.ifr_name);
>> +			perror("F_SETFL, NONBLOCK");
>> +			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);
>> -
>> 	return fd;
>> 
>> error:
>> @@ -512,7 +513,7 @@ 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->name, qid);
>> 			if (fd < 0) {
>> 				RTE_LOG(ERR, PMD, "tun_alloc(%s) failed\n",
>> pmd->name); return -1;
>> @@ -711,7 +712,7 @@ eth_dev_tap_create(const char *name, char *tap_name)
>> 	snprintf(dev->data->name, sizeof(dev->data->name), "%s", name);
>> 
>> 	/* Create the first Tap device */
>> -	fd = tun_alloc(tap_name);
>> +	fd = tun_alloc(tap_name, 0);
>> 	if (fd < 0) {
>> 		RTE_LOG(ERR, PMD, "tun_alloc() failed\n");
>> 		goto error_exit;
>> @@ -739,6 +740,8 @@ eth_dev_tap_create(const char *name, char *tap_name)
>> error_exit:
>> 	RTE_PMD_DEBUG_TRACE("Unable to initialize %s\n", name);
>> 
>> +	if (fd > 0)
>> +		close(fd);
>> 	rte_free(data);
>> 	rte_free(pmd);
>> 
> 
> The patch looks good to me.
> 
> Can you maybe detail in the commit log that now queue 0 is created while
> probing, while other queues are handled through tap_setup_queue() only?

In my changes before your patch set I had removed creating queue 0 at probe and only created the interface/queue at queue setup time. It would have required a more changes compared to your patches and the original code. :-(

> 
> Pascal

Regards,
Keith



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