linux-kernel - Re: [PATCH v3] USB: Extend usb_device_speed with new value USB_SPEED_SUPER_PLUS

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: <20230901223316.vbnf3zfjsxoogenb@synopsys.com>
Date:   Fri, 1 Sep 2023 22:33:30 +0000
From:   Thinh Nguyen <Thinh.Nguyen@...opsys.com>
To:     Dingyan Li <18500469033@....com>
CC:     "stern@...land.harvard.edu" <stern@...land.harvard.edu>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "mathias.nyman@...el.com" <mathias.nyman@...el.com>,
        "pawell@...ence.com" <pawell@...ence.com>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "brcm80211-dev-list.pdl@...adcom.com" 
        <brcm80211-dev-list.pdl@...adcom.com>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "mina86@...a86.com" <mina86@...a86.com>,
        "clemens@...isch.de" <clemens@...isch.de>,
        "ruslan.bilovol@...il.com" <ruslan.bilovol@...il.com>,
        "bigeasy@...utronix.de" <bigeasy@...utronix.de>,
        "treding@...dia.com" <treding@...dia.com>,
        "oneukum@...e.com" <oneukum@...e.com>,
        "laurent.pinchart@...asonboard.com" 
        <laurent.pinchart@...asonboard.com>,
        "nic_swsd@...ltek.com" <nic_swsd@...ltek.com>,
        "marcel@...tmann.org" <marcel@...tmann.org>
Subject: Re: [PATCH v3] USB: Extend usb_device_speed with new value
 USB_SPEED_SUPER_PLUS_BY2

Hi,

Please Cc me for changes related to dwc3.

On Sat, Sep 02, 2023, Dingyan Li wrote:
> Currently there are there major generations when speaking of
> USB_SPEED_SUPER_PLUS devices. However, they actually stands
> for different physical speeds. GEN_2x2 means 20Gbps, while
> the others mean 10Gbps. So in order to confirm 20Gbps, both
> speed and generation need ti be checked. This causes a trouble
> for ioctl USBDEVFS_GET_SPEED since it can only return speed
> value to userspace.
> 
> In order not to add a new ioctl to get ssp generation, extending
> usb_device_speed is a good option. The side effect is that
> USB_SPEED_SUPER_PLUS has been used in lots of places and
> it also takes some effort to go through all of them and check
> whether the new speed should be used too.
> 
> Besides, as suggested by Alen, ssp_rate is not a proper name,
> change it to ssp_gen. And change all functions/struct fileds
> ended with ssp_rate to ssp_gen. And there is also some code
> refactor to reduce duplicate definition of strings and increase
> the utilization of commonly defined utilities.
> 
> Signed-off-by: Dingyan Li <18500469033@....com>
> ---

Can we spell out the whole thing instead of USB_SPEED_SUPER_PLUS_BY2
(ie. USB_SPEED_SUPER_PLUS_GEN_2x2 as you intended) instead of just the
lane count.

There are SuperSpeed Plus generation _and_ lane count. That's why I
didn't name "usb_ssp_gen" that only reflects the generation and not the
lane count. Also, I didn't extend usb_device_speed because gen XxY are
all a single speed: SuperSpeed Plus.

If you're planning to do it this way, why not add the other speeds (such
as gen 1x2) to usb_device_speed enum too? Then we can drop the
usb_ssp_rate enum. If we're going to check multiple enum for SuperSpeed
Plus, we probably need a usb_device_is_superspeed_plus() function.

Now we need to audit all the greater/lesser speed checks that use < or >
to make sure that they are used how they were intended to.

Since these changes are not simple and will touch on multiple places,
please split this patch out.

Thanks,
Thinh