From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id 2563498 for ; Tue, 31 Jan 2017 16:38:43 +0100 (CET) Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga105.fm.intel.com with ESMTP; 31 Jan 2017 07:38:43 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,315,1477983600"; d="scan'208";a="928584784" Received: from fyigit-mobl1.ger.corp.intel.com (HELO [10.237.220.38]) ([10.237.220.38]) by orsmga003.jf.intel.com with ESMTP; 31 Jan 2017 07:38:42 -0800 To: Pascal Mazon , keith.wiles@intel.com References: <1485855778-15496-1-git-send-email-pascal.mazon@6wind.com> <39a46c11-66c4-d8ed-a2bc-d9421cb4afd0@6wind.com> Cc: dev@dpdk.org From: Ferruh Yigit Message-ID: <9fa2c783-349c-e20c-0e57-0c24e67a4683@intel.com> Date: Tue, 31 Jan 2017 15:38:41 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH 1/6] net/tap: use correct tap name X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 31 Jan 2017 15:38:44 -0000 On 1/31/2017 3:30 PM, Pascal Mazon wrote: > On 01/31/2017 04:28 PM, Ferruh Yigit wrote: >> On 1/31/2017 2:23 PM, Pascal Mazon wrote: >>> On 01/31/2017 02:06 PM, Ferruh Yigit wrote:> On 1/31/2017 9:42 AM, >>> Pascal Mazon wrote: >>>>> dev->data->name contains "net_tap", the device driver name. >>>> >>>> I see what patch does, just as a note to commit log: >>>> >>>> AFAIK, "dev->data->name" is device name, and for this case it is >>>> "net_tap#", like "net_tap0", "net_tap1" ... >>>> >>>> "dev->data_drv_name" is the driver name which is "net_tap" >>> >>> Indeed, dev->data->name is the device name, looking like "net_tap#", >>> with number increasing for each vdev. >>> I'll put the following commit log line if that's ok: >>> >>> dev->data->name contains the device name, e.g. "net_tap0". >>> >>>> >>>>> dev->data->dev_private->name contains the actual iface name, >>>>> e.g. "dtap0". >>>> >>>> Right, I agree this is correct comparing "dev->data->name" >>>> >>>> But the problem is pmd->name is per eth_dev. >>>> >>>> If I read code correct, for multiple queue support, each queue pair will >>>> create a tap device, so each needs a different name. >>>> >>>> So can't just use pmd->name. Need to create a name per queue pair, it >>>> can be combination of pmd->name + "_" + queue_id? Or can keep a name per >>>> queue pair, instead of eth_dev. >>>> >>>> What do you think? >>> >>> Actually that's not exactly how it goes. >>> Adding a queue to a netdevice requires to open("/dev/net/tun") and setting >>> TUNSETIFF (through ioctl) on the resulting fd. >>> That's the important part: queues for a given tap device must set TUNSETIFF >>> with a common ifreq.ifr_name (in our case, pmd->name). >>> >>> This is best explained in the kernel doc, there: >> >> Thank you for the clarification. >> If so, why PMD keeps a fd per queue? >> >> Overall, patch looks good except mentioned detail in commit log. >> >> I suggest waiting Keith's patch, and rebase this set on top of it. >> >> Thanks, >> ferruh >> >>> >>> [1] >>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/tuntap.txt#n108 >>> >> <...> >> > > I would say it is because dev->{r/t}x_pkt_burst() is done per queue. > In these functions, we need to make our read() and write() accesses on the > right fd considering the queue we're required to process. If fd is same for all queues, it is possible to keep one instance in pmd private_data, and access it from queues. I think it is confusing to have multiple copy of it, but I see your point. > > I'll wait for Keith's patch, then. Thanks again. > > Best regards, >