On Sun, Jun 12, 2022 at 7:13 PM Oliver Hartkopp <socketcan@xxxxxxxxxxxx> wrote: > > > > On 12.06.22 18:23, Max Staudt wrote: > > On Sat, 11 Jun 2022 12:46:04 +0200 > > Dario Binacchi <dario.binacchi@xxxxxxxxxxxxxxxxxxxx> wrote: > > > >>> As written before I would like to discuss this change out of your > >>> patch series "can: slcan: extend supported features" as it is no > >>> slcan feature extension AND has to be synchronized with the > >>> drivers/net/slip/slip.c implementation. > >> > >> Why do you need to synchronize it with drivers/net/slip/slip.c > >> implementation ? > > > > Because slcan.c is a derivative of slip.c and the code still looks > > *very* similar, so improvements in one file should be ported to the > > other and vice versa. This has happened several times now. > > > > > >>> When it has not real benefit and introduces more code and may create > >>> side effects, this beautification should probably be omitted at all. > >>> > >> > >> I totally agree with you. I would have already dropped it if this > >> patch didn't make sense. But since I seem to have understood that > >> this is not the case, I do not understand why it cannot be improved > >> in this series. > > > > This series is mostly about adding netlink support. If there is a point > > of contention about a beautification, it may be easier to discuss that > > separately, so the netlink code can be merged while the beautification > > is still being discussed. > > > > > > On another note, the global array of slcan_devs is really unnecessary > > and maintaining it is a mess - as seen in some of your patches, that > > have to account for it in tons of places and get complicated because of > > it. > > > > slcan_devs is probably grandfathered from a very old kernel, since > > slip.c is about 30 years old, so I suggest to remove it entirely. In > > fact, it may be easier to patch slcan_devs away first, and that will > > simplify your open/close patches - your decision :) > > > > > > If you wish to implement the slcan_devs removal, here are some hints: > > > > The private struct can just be allocated as part of struct can_priv in > > slcan_open(), like so: > > > > struct net_device *dev; > > dev = alloc_candev(sizeof(struct slcan), 0); > > > > And then accessed like so: > > > > struct slcan *sl = netdev_priv(dev); > > > > Make sure to add struct can_priv as the first member of struct slcan: > > > > /* This must be the first member when using alloc_candev() */ > > struct can_priv can; > > > > > >> The cover letter highlighted positive reactions to the series because > >> the module had been requiring these kinds of changes for quite > >> some time. So, why not take the opportunity to finalize this patch in > >> this series even if it doesn't extend the supported features ? > > > > Because... I can only speak for myself, but I'd merge all the > > unambiguous stuff first and discuss the difficult stuff later, if there > > are no interdependencies :) > > > > > > > > Max > > > > Thanks for stepping in Max! > > Couldn't have summarized it better ;-) > > When I created slcan.c from slip.c this line discipline driver was just > oriented at the SLIP idea including the user space tools to attach the > network device to the serial tty. > > Therefore the driver took most of the mechanics (like the slcan_devs > array) and did *only* the 'struct canframe' to ASCII conversion (and > vice versa). > > @Dario: Implementing the CAN netlink API with open/close/bitrate-setting > is a nice improvement. Especially as you wrote that you took care about > the former/old API with slcan_attach/slcand. > > Best regards, > Oliver Thanks to both of you for the explanations. best regards, Dario -- Dario Binacchi Embedded Linux Developer dario.binacchi@xxxxxxxxxxxxxxxxxxxx __________________________________ Amarula Solutions SRL Via Le Canevare 30, 31100 Treviso, Veneto, IT T. +39 042 243 5310 info@xxxxxxxxxxxxxxxxxxxx www.amarulasolutions.com
