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

[Pascal Mazon]

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?

Pascal