netdev - Re: [PATCH net-next 5/9] net: hns3: refactor flow director configuration

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210315130027.669b8afa@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Date:   Mon, 15 Mar 2021 13:00:27 -0700
From:   Jakub Kicinski <kuba@...nel.org>
To:     Huazhong Tan <tanhuazhong@...wei.com>
Cc:     <davem@...emloft.net>, <netdev@...r.kernel.org>,
        <salil.mehta@...wei.com>, <yisen.zhuang@...wei.com>,
        <huangdaode@...wei.com>, <linuxarm@...neuler.org>,
        <linuxarm@...wei.com>, Jian Shen <shenjian15@...wei.com>
Subject: Re: [PATCH net-next 5/9] net: hns3: refactor flow director
 configuration

On Mon, 15 Mar 2021 20:23:47 +0800 Huazhong Tan wrote:
> From: Jian Shen <shenjian15@...wei.com>
> 
> Currently, there are 3 flow director work modes in HNS3 driver,
> include EP(ethtool), tc flower and aRFS. The flow director rules
> are configured synchronously and need holding spin lock. With this
> limitation, all the commands with firmware are also needed to use
> spin lock.
> 
> To eliminate the limitation, configure flow director rules
> asynchronously. The rules are still kept in the fd_rule_list
> with below states.
> TO_ADD: the rule is waiting to add to hardware
> TO_DEL: the rule is waiting to remove from hardware
> ADDING: the rule is adding to hardware
> ACTIVE: the rule is already added in hardware
> 
> When receive a new request to add or delete flow director rule,
> check whether the rule location is existent, update the rule
> content and state, and request to schedule the service task to
> finish the configuration.
> 
> Signed-off-by: Jian Shen <shenjian15@...wei.com>
> Signed-off-by: Huazhong Tan <tanhuazhong@...wei.com>

How is the application supposed to know if the ethtool rule was already
installed or installation is still pending?

With the firmware bloat on all devices this sort of async mechanism
seems to be popping up in more and more drivers but IMHO we shouldn't
weaken the semantics without amending the kernel <> user space API.