disksort disappeared from ATA devices in HEAD ?

I notice that the ata drivers in HEAD do not use anymore
bioq_disksort, but rather they have their own routine,
(ad_queue_request() in turn calling ata_sort_queue())
which probably does something similar.

I wonder:
1) how different is ata_sort_queue() from bioq_disksort()
   in terms of design ?
2) is there any strong reason for this change ?
3) any pointers to mail threads where this changes have been
   discussed ?

I cannot find any relevent comments browsing the code or CVS.
the change was introduced here

+++ src/sys/dev/ata/ata-disk.c	2005/03/30 12:03:37	1.183

so not long ago...

	cheers
	luigi