Messages in this thread | | | Date | Wed, 22 Jun 2005 01:14:12 -0700 | From | Greg KH <> | Subject | Re: [patch 1/16] s390: klist bus_find_device & driver_find_device callback. |
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On Wed, Jun 22, 2005 at 09:48:02AM +0200, Cornelia Huck wrote: > Greg KH <greg@kroah.com> 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.
Ah, now I get it. "later use" is the key point here. I was thinking you could do whatever you want within the callback. But if you want to do something later on with this pointer, that would be very tough.
Hm, I could use this kind of function, as I had to jump through a few hoops when iterating over all devices on a bus, when I just wanted to find a specific device (it involved creating a temp structure on the stack and doing my logic in the callback function itself, for details see http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/driver/driver-bind.patch for a patch that adds manual binding of drivers to devices from userspace through sysfs. With this function it should get even smaller.)
> > 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 > caller...
Care to fix this up and resend it?
Sorry for the misunderstanding.
thanks,
greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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