From owner-freebsd-scsi Sun Oct 5 03:21:00 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id DAA11250 for freebsd-scsi-outgoing; Sun, 5 Oct 1997 03:21:00 -0700 (PDT) Received: from sax.sax.de (sax.sax.de [193.175.26.33]) by hub.freebsd.org (8.8.7/8.8.7) with SMTP id DAA11242 for ; Sun, 5 Oct 1997 03:20:52 -0700 (PDT) Received: (from uucp@localhost) by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id MAA01267 for freebsd-scsi@FreeBSD.ORG; Sun, 5 Oct 1997 12:20:51 +0200 Received: (from j@localhost) by uriah.heep.sax.de (8.8.7/8.8.5) id LAA29323; Sun, 5 Oct 1997 11:56:00 +0200 (MET DST) Message-ID: <19971005115559.AS58851@uriah.heep.sax.de> Date: Sun, 5 Oct 1997 11:55:59 +0200 From: j@uriah.heep.sax.de (J Wunsch) To: freebsd-scsi@FreeBSD.ORG Subject: Re: New SCSI Framework Patches Available References: <199710031157.VAA02092@gurney.reilly.home> <199710031835.MAA04392@pluto.plutotech.com> X-Mailer: Mutt 0.60_p2-3,5,8-9 Mime-Version: 1.0 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) In-Reply-To: <199710031835.MAA04392@pluto.plutotech.com>; from Justin T. Gibbs on Oct 3, 1997 12:35:09 -0600 Sender: owner-freebsd-scsi@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk As Justin T. Gibbs wrote: > So, the question is how to best handle the problem? I would prefer a transition from b_blkno to b_offset, thereby eliminating all the ``shift right here, shift back left there'' mess completely. The drawback is that b_offset needs to be 64 bits, so naturally this will lead to more bloat and slower execution on 32-bit CPUs. The second problem is that b_blkno is being abused in quite a number of places (see b_lblkno and b_pblkno), making it more work to do the transition. Of course, the latter can be thought of as an advantage, in that it requires some code cleanup. ;-) The advantage (besides of achieving the goal to support arbitrary block sizes) is that the code will be cleaner. The 64-bit problem will no longer be a problem once running on a 64-bit CPU. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)