Ответ: "mdev -s" fails to create /dev entries

Vladimir Dronnikov dronnikov at gmail.com
Sat Jul 12 10:54:13 UTC 2008


As a indirect volunteer, I revive the idea of having config_parse()
stuff proposed earlier.
That way we uniformly parse config and then use "compiled" config for
devices being discovered. It is a good challenge to elaborate config
file processing.

I recall Tito has advanced significantly...
And my patch is still "under the glass"...

--
Vladimir

2008/7/12, Denys Vlasenko <vda.linux at googlemail.com>:
> On Saturday 12 July 2008 10:06, Holland, John wrote:
>> >> That is when you stay within /sys/class or /sys/block. Operating on the
>> >> whole of /sys and following non-symlinks only will and does find all
>> >> dev
>> >> files reliably (don't know about the above mentioned loop devices).
>> >
>> >Ok, I'll bite.  If you look under /sys/devices for "dev" nodes, how do
>> > you
>> >tell if you've got a char device or a block device?  (I'd really like to
>> >know.)
>>
>> As Vladimir previously posted they too have '/block/' somewhere in their
>> non-symlink path (i.e. loop devices on 2.6.25). This must be thoroughly
>> tested.
>
> You convinced me that testing for "/block/" in the name
> will be more reliable - kernel people are unlikely to have that
> in char device name. I hope.
>
>> >(This is glossing over the fact that searching through an arbitrarily
>> >large /sys tree could be very slow on certain systems, and a lot of
>> > embedded
>> >stuff is using 100 mhz processors and such, and prefer mdev to udev for
>> > the
>> >_speed_ as much as for the memory savings.)
>>
>> You're right... However, those tiny systems normally do not have the
>> number
>> of devices/modules as the others. If you wish, we could leave dirAction
>> and
>> redefine it not to walk through certain directories ('/modules/').
>>
>> For me, speed is secondary. I'd prefer that mdev works as intended on many
>> kernels, w/o having to worry if mdev will work on some forthcoming kernel.
>
> You cannot neglect other user's needs like that.
>
> Let's implement strstr("/block/") thing but restrict the scan to /sys/block
> and /sys/class for now.
>
> BTW: there is a speedup opportunity in mdev -s: we parse config file
> repeatedly
> (which includes compiling regexp) for each device scanned!
> Volunteers to fix that?
> --
> vda
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