Re: [patch 1/16] s390: klist bus_find_device & driver_find_device callback.

From: Cornelia Huck
Date: Wed Jun 22 2005 - 03:07:54 EST

Greg KH <greg@xxxxxxxxx> wrote on 22.06.2005 08:26:27:

> What's wrong with just using bus_for_each_dev() instead? You have to
> supply a "match" type function anyway, so the caller doesn't have an
> easier time using this function instead.

Maybe it's just too early in the morning, but I don't see how I could
achive what I want to do with bus_for_each_dev(). The idea behind
bus_find_device() is to scan the bus for a device matching some
criterium and to return a pointer to it with which the caller can
continue to work. bus_for_each_dev() calls the match function for
every device until we abort, but I don't see how I can grab a reference
to a specific device for later use.

> You also don't increment the reference properly when you return the
> pointer, so you better document that... :(

You're right, this should be done in the base code and not by the

> In short, I don't think this is needed at all, as it's an almost
> identical copy of bus_for_each_dev().

It looks similar, yes, but they are for different purposes:
- bus_for_each_dev(): do something for each device (as specified
in the callback function)
- bus_find_device(): get a reference to a specific device for later
use (as matched in the callback function)

> Same comment as above, I don't think this function is necessary.

Same comment from me, I think I need this interface for drivers
as well.

> thanks,
> greg k-h


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