Dear Thomas, Thanks for your answer. It took me a little time to digest answer. Please see inline.
> 21/09/2018 09:19, Hideyuki Yamashita: > > Dear Gaetan and Thomas, > > > > Thanks for your answer. > > Please see inline. > > > > > 20/09/2018 11:09, Ga?an Rivet: > > > > On Thu, Sep 20, 2018 at 05:46:37PM +0900, Hideyuki Yamashita wrote: > > > > > Hello, > > > > > > > > > > From dpdk 18.08 release rte_eth_dev_attach and > > > > > rte_eth_dev_detach becom deprecated API and > > > > > it is recommended to replace with rte_eal_hotplug_add > > > > > and rte_eal_hotplug_remove. > > > > > > > > > > My program uses above mentioned deprecated APIs > > > > > and have to replace those. > > > > > Note that my program uses attach to attach vhost, pcap pmd. > > > > > > > > > > My question is whether it is correct to replace those as following: > > > > > find rte_eth_dev_attach function in rte_ethdev.c and > > > > > migrate those content into my program. > > > > > > > > > > e.g. > > > > > lib/librte_ethdev/rte_ethdev.c line 643-686 for attach > > > > > lib/librte_ethdev/rte_ethdev.c line 690-720 for detach > > > > > > > > > > Your advice/guidance are much appreciated. > > > > > Thanks! > > > > > > > > Hello Hideyuki, > > > > > > > > You could use this code for guidance, while leaving the ethdev > > > > specificities such as verifying the eth_dev_count_total(). The hotplug > > > > function would already return an error if the PMD was not able to create > > > > the necessary devices. > > > > > > > > The main issue might be to find the port_id of your new port. > > > > You won't be able to use eth_dev_last_created_port, so you would have to > > > > iterate over the ethdev using RTE_ETH_FOREACH_DEV and find the one > > > > matching your parameters (you might for example match the rte_device > > > > name with the name you used in hotplug_add, as there is no standard > > > > naming scheme at the ethdev level). > > First of all, thank for your answering to my question. > > But I have questions. > > (Sorry, I have poor knowledge about dpdk and have many basic questions) > > > > Q1. > > Why eth_dev_last_created_port can not be used? > > When I look into rte_eth_dev_atthach in 18.08, it calls > > > > *port_id = eth_dev_last_created_port; > > > > at the end of the function. > > You can have a race condition. Please elaborate me a bit more. Is it correct understanding that race condition includes - read information before port is available - other device may be plugged (or unplugged) and so using "eth_dev_last_created_port" is NOT reliable? > > Q2. > > Is it possible to use rte_eth_dev_get_port_by name > > instead of calling RTE_ETH_FOREACH_DEV or using > > eth_dev_last_created_port? > > This function works only if you know the ethdev name generated by the PMD. Thanks > > Q3. > > If answer to Q2 is no, then how can I get device name from each device? > > For example, rte_eth_dev_info_get takes port_id as its > > argument.But what I want to know is the port id of the specified device > > name. > > If you want the ethdev port ids created after probing (based on devargs), > you probably want to request it with the same devargs. > I will try to work on something for this need. > For now, the most reliable solution is to use the notifications. I think I have two alternatives: Alt1: call "rte_eal_hotplug_add" and retrieve port_id for newly plugged device using RTE_ETH_FOREACH_DEV. (as Gaetan said) Alt2: call "rte_eth_dev_callback_register" to subscribe "port probe" event and "rte_eal_hotplug_add" and finally get notification including port id. (As you said) My question is which is better alternative? Are there any bad point on Alt1 like using eth_dev_last_created_port? (e.g. port not available when called RTE_ETH_FOREACH_DEV) BR, Hideyuki Yamashita NTT TechnoCross > > > It is recommended to register a callback to receive the notifications > > > of new ethdev ports. > > > So it may be a change of programming style: sync vs async. > > Thanks for your advice. > > In general, I agree. > > > > But what is the example of notification that program can receive > > after device hotplugged? > > Device unplugged notification like specified in rte_eth_event_type? > > Yes, look at these ones: > RTE_ETH_EVENT_NEW, /**< port is probed */ > RTE_ETH_EVENT_DESTROY, /**< port is released */ > > > If there are code in example, it is highly appreciated. > > You can register a callback with > rte_eth_dev_callback_register(RTE_ETH_ALL, RTE_ETH_EVENT_NEW, ...) > like done in drivers/net/failsafe/failsafe.c > > >
