DPDK patches and discussions
 help / color / mirror / Atom feed
From: Ferruh Yigit <ferruh.yigit@intel.com>
To: "Gaëtan Rivet" <grive@u256.net>
Cc: dev@dpdk.org, stable@dpdk.org, thomas@monjalon.net
Subject: Re: [dpdk-dev] [dpdk-stable] [PATCH v1 2/3] net/ring: fix eth_dev device pointer on allocation
Date: Wed, 6 May 2020 14:43:19 +0100	[thread overview]
Message-ID: <e1d133f8-c6b1-4d24-0fa0-053ba46f0315@intel.com> (raw)
In-Reply-To: <20200506123344.6ui6wfhwevawbyoh@u256.net>

On 5/6/2020 1:33 PM, Gaëtan Rivet wrote:
> On 06/05/20 12:48 +0100, Ferruh Yigit wrote:
>> On 5/5/2020 8:10 PM, Gaetan Rivet wrote:
>>> When a net_ring device is allocated, its device pointer is not set
>>> before calling rte_eth_dev_probing_finish, which is incorrect.
>>>
>>> The following:
>>>   commit: 96cb19521147 ("net/ring: use EAL APIs in PMD specific API")
>>>   commit: a6992e961050 ("net/ring: set ethernet device field")
>>>
>>> already attempted to fix this issue in 17.08, which was fine at the
>>> time. Adding the hook rte_eth_dev_probing_finish() however created this
>>> bug, as the eth_dev exposed when this hook is executed is expected to be
>>> complete.
>>>
>>> Remove the prior attempts to fix the issue in rte_pmd_ring_probe() and
>>> write the pointer properly in do_eth_dev_ring_create().
>>>
>>> Cc: stable@dpdk.org
>>> Fixes: fbe90cdd776c ("ethdev: add probing finish function")
>>> Cc: ferruh.yigit@intel.com
>>> Cc: thomas@monjalon.net
>>> Signed-off-by: Gaetan Rivet <grive@u256.net>
>>
>> <...>
>>
>>> @@ -325,10 +346,17 @@ do_eth_dev_ring_create(const char *name,
>>>  	data->kdrv = RTE_KDRV_NONE;
>>>  	data->numa_node = numa_node;
>>>  
>>> -	/* finally assign rx and tx ops */
>>> +	/* assign rx and tx ops */
>>>  	eth_dev->rx_pkt_burst = eth_ring_rx;
>>>  	eth_dev->tx_pkt_burst = eth_ring_tx;
>>>  
>>> +	/* finally set the rte_device pointer in eth_dev. */
>>> +	eth_dev->device = ring_device_from_name(name);
>>> +	if (eth_dev->device == NULL) {
>>> +		rte_errno = ENODEV;
>>> +		goto error;
>>> +	}
>>> +
>>>  	rte_eth_dev_probing_finish(eth_dev);
>>>  	*eth_dev_p = eth_dev;
>>
>> Why not move the 'rte_eth_dev_probing_finish()' to the 'rte_pmd_ring_probe()',
>> below where 'eth_dev->device' set?
> 
> Hi Ferruh,
> 
> Sure it would work. The reason I did it this way is two-fold:
> 
>   * I disliked having two places where eth_dev->device was conditionally
>     set. It makes it harder to read rte_pmd_ring_probe.

Agree, what about using a 'goto' to have the assignment and
'rte_eth_dev_probing_finish()' in a single place?
But check seems needed since creation may failed at that stage, if you think
better check can be done on 'ret' instead of 'eth_dev'...

> 
>   * I was actually thinking, doing this patch, that we should modify
>     rte_eth_dev_allocate() to take an rte_device as parameter, as all
>     eth_dev are meant to be backed by an rte_device. Keeping this in
>     mind, I meant to move writing the pointer closer to the
>     rte_eth_dev_allocate() call.

That is a bigger change, may affect many (if not all) PMDs, so I think this can
be considered when that change is available.

And although that change may fix the issues that 'eth_dev->device' is not set,
which we had a few times before, not sure it worth to change all PMDs and ethdev
API directly couple with rte_device, instead of PMD being the glue. Can be
discussed more on its own patch.

> 
> But you are right that it is needlessly verbose, using
> vdev_bus->find_device() to do this stuff. I'm ok with changing it as you
> described if you prefer.
> 

That was the concern, that is too much code to take a value which is already
available a few level up the stack.

  reply	other threads:[~2020-05-06 13:43 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-27 10:44 [dpdk-dev] [PATCH] net/failsafe: fix fd leak wangyunjian
2020-04-27 11:12 ` Gaëtan Rivet
2020-04-27 16:55   ` [dpdk-dev] [dpdk-stable] " Ferruh Yigit
2020-05-03 11:33     ` Ali Alnubani
2020-05-04 16:22       ` Gaëtan Rivet
2020-05-04 16:28         ` Stephen Hemminger
2020-05-05  9:47           ` Ali Alnubani
2020-05-05  9:14         ` Ali Alnubani
2020-05-05 18:35           ` Gaëtan Rivet
2020-05-05 19:10       ` [dpdk-dev] [PATCH v1 0/3] failsafe & ring fixes Gaetan Rivet
2020-05-05 19:10         ` [dpdk-dev] [PATCH v1 1/3] net/failsafe: avoid crash on malformed eth_dev Gaetan Rivet
2020-05-06 17:16           ` Ferruh Yigit
2020-05-05 19:10         ` [dpdk-dev] [PATCH v1 2/3] net/ring: fix eth_dev device pointer on allocation Gaetan Rivet
2020-05-06 11:48           ` Ferruh Yigit
2020-05-06 12:33             ` Gaëtan Rivet
2020-05-06 13:43               ` Ferruh Yigit [this message]
2020-05-06 17:32                 ` [dpdk-dev] [dpdk-stable] " Gaëtan Rivet
2020-05-06 18:09                   ` [dpdk-dev] [PATCH v2] " Gaetan Rivet
2020-05-08 11:00                     ` Ferruh Yigit
2020-05-11 16:54                       ` Ferruh Yigit
2020-05-05 19:10         ` [dpdk-dev] [PATCH v1 3/3] net/failsafe: fix default service proxy state Gaetan Rivet
2020-05-06  8:58           ` Ali Alnubani
2020-05-06 17:16           ` Ferruh Yigit

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=e1d133f8-c6b1-4d24-0fa0-053ba46f0315@intel.com \
    --to=ferruh.yigit@intel.com \
    --cc=dev@dpdk.org \
    --cc=grive@u256.net \
    --cc=stable@dpdk.org \
    --cc=thomas@monjalon.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).