From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Schiller Subject: Re: [PATCH net-next RFC v4] net: hdlc_x25: Queue outgoing LAPB frames Date: Tue, 02 Mar 2021 08:04:20 +0100 Message-ID: <41b77b1c3cf1bb7a51b750faf23900ef@dev.tdt.de> References: <20210216201813.60394-1-xie.he.0141@gmail.com> <20210219103948.6644e61f@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <906d8114f1965965749f1890680f2547@dev.tdt.de> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Xie He Cc: Jakub Kicinski , Leon Romanovsky , "David S. Miller" , Linux X25 , Linux Kernel Network Developers , LKML , Krzysztof Halasa , Jonathan Corbet , linux-doc@vger.kernel.org On 2021-03-01 09:56, Xie He wrote: > On Sun, Feb 28, 2021 at 10:56 PM Martin Schiller wrote: >> >> >> Also, I have a hard time assessing if such a wrap is really >> >> enforceable. >> > >> > Sorry. I don't understand what you mean. What "wrap" are you referring >> > to? >> >> I mean the change from only one hdlc interface to both hdlc and >> hdlc_x25. >> >> I can't estimate how many users are out there and how their setup >> looks >> like. > > I'm also thinking about solving this issue by adding new APIs to the > HDLC subsystem (hdlc_stop_queue / hdlc_wake_queue) for hardware > drivers to call instead of netif_stop_queue / netif_wake_queue. This > way we can preserve backward compatibility. > > However I'm reluctant to change the code of all the hardware drivers > because I'm afraid of introducing bugs, etc. When I look at the code > of "wan/lmc/lmc_main.c", I feel I'm not able to make sure there are no > bugs (related to stop_queue / wake_queue) after my change (and even > before my change, actually). There are even serious style problems: > the majority of its lines are indented by spaces. > > So I don't want to mess with all the hardware drivers. Hardware driver > developers (if they wish to properly support hdlc_x25) should do the > change themselves. This is not a problem for me, because I use my own > out-of-tree hardware driver. However if I add APIs with no user code > in the kernel, other developers may think these APIs are not > necessary. I don't think a change that affects the entire HDLC subsystem is justified, since the actual problem only affects the hdlc_x25 area. The approach with the additional hdlc_x25 is clean and purposeful and I personally could live with it. I just don't see myself in the position to decide such a change at the moment. @Jakub: What is your opinion on this.