On Fri, Dec 22, 2017 at 11:29:38AM +0000, Bernard Metzler wrote:
>
> -----Leon Romanovsky <leon@xxxxxxxxxx> wrote: -----
>
> >To: Bernard Metzler <BMT@xxxxxxxxxxxxxx>
> >From: Leon Romanovsky <leon@xxxxxxxxxx>
> >Date: 10/14/2017 08:41AM
> >Cc: linux-rdma@xxxxxxxxxxxxxxx
> >Subject: Re: [PATCH v2 03/13] Attach/detach SoftiWarp to/from network
> >and RDMA subsystem
> >
> >On Sat, Oct 14, 2017 at 01:28:43AM +0000, Bernard Metzler wrote:
> >> -----Leon Romanovsky <leon@xxxxxxxxxx> wrote: -----
> >>
> >> >> +
> >> >> +#define SIW_MAX_IF 12
> >> >> +static int if_cnt;
> >> >> +static char *iface_list[SIW_MAX_IF] = {[0 ... (SIW_MAX_IF-1)] =
> >> >'\0'};
> >> >> +module_param_array(iface_list, charp, &if_cnt, 0444);
> >> >> +MODULE_PARM_DESC(iface_list, "Interface list siw attaches to if
> >> >present");
> >> >> +
> >> >> +static bool loopback_enabled = 1;
> >> >> +module_param(loopback_enabled, bool, 0644);
> >> >> +MODULE_PARM_DESC(loopback_enabled, "enable_loopback");
> >> >> +
> >> >> +LIST_HEAD(siw_devlist);
> >> >> +
> >> >> +static int cpu_cnt;
> >> >> +static char *tx_cpu_list[MAX_CPU] = {[0 ... (MAX_CPU-1)] =
> >'\0'};
> >> >> +module_param_array(tx_cpu_list, charp, &cpu_cnt, 0444);
> >> >> +MODULE_PARM_DESC(tx_cpu_list, "List of CPUs siw TX thread shall
> >be
> >> >bound to");
> >> >
> >> >No module parameters please.
> >> OK. Would you have a pointer which sheds some light on that
> >> rule? Thank you!
> >>
> >
> >It is not rule, but common knowledge exactly as BUG_ON which is not
> >prohibited, but makes no sense in low level driver code.
> >
> >The module parameters sometimes make sense, for example in subsystem
> >level where they can apply to whole devices underneath.
> >
> >But most of the time, they indicate complete ignorance of users in
> >favor
> >of easy developer's life.
> >
> >For people, like me, who doesn't run modules at all, the change in
> >module parameters require rebuild of initramfs and in more extreme
> >cases rebuild of SELinux labels.
> >
>
> I will try to finish up a new patch set for siw over
> Christmas holidays.
>
> One question I have - what is the recommended way of replacing
> those module parameters, if we need to flexibly parameterize
> things from user land? For the rxe driver, I see the usage of
> module_param_cb, but this probably is not what we want in the
> long run? Would a sysctl be appropriate, or a char device
> (we may need to pass strings like interface names), or configfs?
It looks like "ip" tool can be good fit, or teach ib/core to accept
parameters from rdmatool before actual device exists.
Thanks
>
> Thanks very much!
> Bernard.
>
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