From: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
To: Jens Axboe <axboe@suse.de>
Subject: Re: [PATCH] fix rq->flags use in ide-tape.c
Date: Wed, 5 Nov 2003 16:16:53 +0100
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On Wednesday 05 of November 2003 14:56, Jens Axboe wrote:
> On Wed, Nov 05 2003, Bartlomiej Zolnierkiewicz wrote:
> > On Wednesday 05 of November 2003 13:00, Bartlomiej Zolnierkiewicz wrote:
> > > On Wednesday 05 of November 2003 09:40, Jens Axboe wrote:
> > > > On Tue, Nov 04 2003, Linux Kernel Mailing List wrote:
> > > > > ChangeSet 1.1413, 2003/11/04 08:01:30-08:00,
> > > > > B.Zolnierkiewicz@elka.pw.edu.pl
> > > > >
> > > > > 	[PATCH] fix rq->flags use in ide-tape.c
> > > > >
> > > > > 	Noticed by Stuart_Hayes@Dell.com:
> > > >
> > > > Guys, this is _way_ ugly. We definitely dont need more crap in
> > > > ->flags for private driver use, stuff them somewhere else in the rq.
> > > > rq->cmd[0] usage would be a whole lot better. This patch should never
> > > > have been merged. If each and every driver needs 5 private bits in
> > > > ->flags, well...
> > >
> > > Yeah, it is ugly.  Using rq->cmd is also ugly as it hides the problem
> > > in ide-tape.c, but if you prefer this way I can clean it up.  I just
> > > wanted minimal changes to ide-tape.c to make it working.
> >
> > Also putting these flags in rq->cmd[0] makes it hard to later convert
> > ide-tape.c to use rq->cmd[] for storing packet commands.
>
> What's wrong with just looking at the opcode instead of inventing magic
> flags. Seems like _just_ the right thing to do, convert to really using
> rq and killing the private command stuff as much as possible. The latter
> can wait though, the flag thing really has to go right now.

It is non-trivial cause it seems packet commands are prepared during
processing request, not prior to queuing it.  Also I still don't fully
understand driver inner-workings with respect to DSC, "pipeline" and internal
commands processing.

> ide-*.c driver by Gadi are all completely over designed and attempts to
> basically implement everything themselves. Horrible.

Yep, but we should be careful in removing cruft.  I've already had a hard time
fixing it after (totally unnecessary and broken) buffer_head->bio conversion.

cheers,
--bartlomiej

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