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From: "Roger B. Melton" <rmelton@cisco.com>
To: Bruce Richardson <bruce.richardson@intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 4/4] ethdev: check support for rx_queue_count and descriptor_done fns
Date: Fri, 12 Jun 2015 13:32:56 -0400	[thread overview]
Message-ID: <557B17C8.3090300@cisco.com> (raw)
In-Reply-To: <1434108496-1993-5-git-send-email-bruce.richardson@intel.com>

Hi Bruce,  Comment in-line.  Regards, Roger

On 6/12/15 7:28 AM, Bruce Richardson wrote:
> The functions rte_eth_rx_queue_count and rte_eth_descriptor_done are
> supported by very few PMDs. Therefore, it is best to check for support
> for the functions in the ethdev library, so as to avoid crashes
> at run-time if the application goes to use those APIs. The performance
> impact of this change should be very small as this is a predictable
> branch in the function.
>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> ---
>   lib/librte_ether/rte_ethdev.h | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
> index 827ca3e..9ad1b6a 100644
> --- a/lib/librte_ether/rte_ethdev.h
> +++ b/lib/librte_ether/rte_ethdev.h
> @@ -2496,6 +2496,8 @@ rte_eth_rx_burst(uint8_t port_id, uint16_t queue_id,
>    *  The queue id on the specific port.
>    * @return
>    *  The number of used descriptors in the specific queue.
> + *  NOTE: if function is not supported by device this call
> + *        returns (uint32_t)-ENOTSUP
>    */
>   static inline uint32_t

Why not change the return type to int32_t?
In this way, the caller isn't required to make the assumption that a 
large queue count indicates an error.  < 0 means error, other wise it's 
a valid queue count.

This approach would be consistent with other APIs.

>   rte_eth_rx_queue_count(uint8_t port_id, uint16_t queue_id)
> @@ -2507,8 +2509,9 @@ rte_eth_rx_queue_count(uint8_t port_id, uint16_t queue_id)
>   		RTE_PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
>   		return 0;
>   	}
> -	RTE_ETH_FPTR_OR_ERR_RET(*dev->dev_ops->rx_queue_count, 0);
>   #endif
> +	RTE_ETH_FPTR_OR_ERR_RET(*dev->dev_ops->rx_queue_count, (uint32_t)-ENOTSUP);
> +
>   	return (*dev->dev_ops->rx_queue_count)(dev, queue_id);
>   }
>   
> @@ -2525,6 +2528,7 @@ rte_eth_rx_queue_count(uint8_t port_id, uint16_t queue_id)
>    *  - (1) if the specific DD bit is set.
>    *  - (0) if the specific DD bit is not set.
>    *  - (-ENODEV) if *port_id* invalid.
> + *  - (-ENOTSUP) if the device does not support this function
>    */
>   static inline int
>   rte_eth_rx_descriptor_done(uint8_t port_id, uint16_t queue_id, uint16_t offset)
> @@ -2536,8 +2540,8 @@ rte_eth_rx_descriptor_done(uint8_t port_id, uint16_t queue_id, uint16_t offset)
>   		RTE_PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
>   		return -ENODEV;
>   	}
> -	RTE_ETH_FPTR_OR_ERR_RET(*dev->dev_ops->rx_descriptor_done, -ENOTSUP);
>   #endif
> +	RTE_ETH_FPTR_OR_ERR_RET(*dev->dev_ops->rx_descriptor_done, -ENOTSUP);
>   
>   	return (*dev->dev_ops->rx_descriptor_done)( \
>   		dev->data->rx_queues[queue_id], offset);

-- 
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  reply	other threads:[~2015-06-12 17:32 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-12 11:28 [dpdk-dev] [PATCH 0/4] ethdev: Add checks for function support in driver Bruce Richardson
2015-06-12 11:28 ` [dpdk-dev] [PATCH 1/4] ethdev: rename macros to have RTE_ETH prefix Bruce Richardson
2015-06-12 11:28 ` [dpdk-dev] [PATCH 2/4] ethdev: move RTE_ETH_FPTR_OR_ERR macros to header Bruce Richardson
2015-06-12 11:28 ` [dpdk-dev] [PATCH 3/4] ethdev: remove duplicated debug functions Bruce Richardson
2015-06-12 11:28 ` [dpdk-dev] [PATCH 4/4] ethdev: check support for rx_queue_count and descriptor_done fns Bruce Richardson
2015-06-12 17:32   ` Roger B. Melton [this message]
2015-06-15 10:14     ` Bruce Richardson
2015-07-06 15:11       ` Thomas Monjalon
2015-07-26 20:44         ` Thomas Monjalon
2015-09-09 15:09 ` [dpdk-dev] [PATCH v2 0/4] ethdev: minor cleanup Bruce Richardson
2015-09-09 15:09   ` [dpdk-dev] [PATCH v2 1/4] ethdev: rename macros to have RTE_ETH prefix Bruce Richardson
2015-09-09 15:09   ` [dpdk-dev] [PATCH v2 2/4] ethdev: move error checking macros to header Bruce Richardson
2015-09-09 15:09   ` [dpdk-dev] [PATCH v2 3/4] ethdev: remove duplicated debug functions Bruce Richardson
2015-09-09 15:09   ` [dpdk-dev] [PATCH v2 4/4] ethdev: check driver support for functions Bruce Richardson
2015-09-28 10:23   ` [dpdk-dev] [PATCH v2 0/4] ethdev: minor cleanup Bruce Richardson
2015-11-03  1:11     ` Thomas Monjalon
2015-11-03 10:06       ` Bruce Richardson
2015-11-03 12:00   ` [dpdk-dev] [PATCH v3 " Bruce Richardson
2015-11-03 12:00     ` [dpdk-dev] [PATCH v3 1/4] ethdev: rename macros to have RTE_ETH prefix Bruce Richardson
2015-11-03 12:00     ` [dpdk-dev] [PATCH v3 2/4] ethdev: move error checking macros to header Bruce Richardson
2015-11-04  1:19       ` Thomas Monjalon
2015-11-04 10:24         ` Adrien Mazarguil
2015-11-04 14:10           ` Bruce Richardson
2015-11-04 15:25             ` Adrien Mazarguil
2015-11-04 18:39           ` Stephen Hemminger
2015-11-05 15:09             ` Adrien Mazarguil
2015-11-05 15:17               ` Bruce Richardson
2015-11-06 11:49               ` Bruce Richardson
2015-11-06 17:10               ` Bruce Richardson
2015-11-06 17:22                 ` Bruce Richardson
2015-11-09 13:39                   ` Adrien Mazarguil
2015-11-09 13:50                     ` Adrien Mazarguil
2015-11-09 14:02                     ` Richardson, Bruce
2015-11-10 10:31                       ` Declan Doherty
2015-11-10 16:08                       ` Adrien Mazarguil
2015-11-10 16:21                         ` Richardson, Bruce
2015-11-10 17:12                           ` Adrien Mazarguil
2015-11-11 10:51                             ` Bruce Richardson
2015-11-03 12:00     ` [dpdk-dev] [PATCH v3 3/4] ethdev: remove duplicated debug functions Bruce Richardson
2015-11-03 12:00     ` [dpdk-dev] [PATCH v3 4/4] ethdev: check driver support for functions Bruce Richardson
2015-11-03 22:00       ` Stephen Hemminger
2015-11-04 14:15         ` Bruce Richardson
2015-11-17 12:21     ` [dpdk-dev] [PATCH v4 0/2] ethdev: debug code cleanup Bruce Richardson
2015-11-17 12:21       ` [dpdk-dev] [PATCH v4 1/2] ethdev: remove duplicated debug functions Bruce Richardson
2015-11-17 12:21       ` [dpdk-dev] [PATCH v4 2/2] ethdev: add sanity checks to functions Bruce Richardson
2015-11-17 15:53         ` Stephen Hemminger
2015-11-24 14:56           ` Bruce Richardson
2015-11-24 15:29             ` Thomas Monjalon
2015-11-24 15:45               ` Bruce Richardson
2015-11-24 15:48                 ` Thomas Monjalon
2015-11-24 17:37       ` [dpdk-dev] [PATCH v5 0/2] ethdev: debug code cleanup Bruce Richardson
2015-11-24 17:37         ` [dpdk-dev] [PATCH v5 1/2] ethdev: remove duplicated debug functions Bruce Richardson
2015-11-25 18:14           ` Thomas Monjalon
2015-11-24 17:37         ` [dpdk-dev] [PATCH v5 2/2] ethdev: add sanity checks to functions Bruce Richardson
2015-11-25 18:21         ` [dpdk-dev] [PATCH v5 0/2] ethdev: debug code cleanup Thomas Monjalon

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