mdev scan

[Denys Vlasenko]

On Friday 04 July 2008 13:39, Holland, John wrote:
> Hi,
> 
> I'm having problems scanning usb_endpoint '/dev's on older kernels, 2.6.13 in particular.
> The usb_endpoints are beyond the constant MAX_SYSFS_DEPTH somewhere under /sys.

How much is ok on those kernels? 4? 5?

> Is there any particular reason for scanning /sys/block and /sys/class separately other than
> to ascertain a nodes type?

I guess scanning whole /sys will go into e.g. /sys/module too
and it can be rather deep.

> Assuming a particular <name>/dev combination is unambiguous, one could scan the entire /sys tree
> without missing any '/dev's. I see three prerequisites.

Can you re-formulate your thoughts is a simpler way? By now, I don't
understand what is the problem you are trying to solve.

> The first is to ignore links while traversing,

Yeah, pity mdev author forgot to document why ACTION_FOLLOWLINKS
is necessary (example would be most useful).
Now we need to guess whether it's real necessity or just an oversight...

> the second is to drop the maximal search depth and last determine a nodes type by searching 
> for '/block/' in the first len('/class/block/') characters in the resulting search path.
> 
> A solution may however, result in longer scan times, but reduces executable size and code complexity.

Solution for what problem?
--
vda