Re: [patch 2/6] ide: fix ide_kill_rq() for special ide-{floppy,tape} driver requests

Bartlomiej Zolnierkiewicz
2009-06-24T10:04:18Z

On Wednesday 24 June 2009 08:49:29 David Miller wrote:
> From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> Date: Tue, 23 Jun 2009 23:26:06 +0200
>
> > @@ -152,7 +152,7 @@ void ide_kill_rq(ide_drive_t *drive, str
> >
> > if ((media == ide_floppy || media == ide_tape) && drv_req) {
> > rq->errors = 0;
> > - ide_complete_rq(drive, 0, blk_rq_bytes(rq));
> > + ide_complete_rq(drive, -EIO, blk_rq_bytes(rq));
> > } else {
> > if (media == ide_tape)
> > rq->errors = IDE_DRV_ERROR_GENERAL;
>
> I've done some research and this logic of returning "0" appears to be
> intentional.
>
> It keeps the block layer from printing the "I/O error" kernel log
> message during completion of the request.

It would be pretty illogical behavior for driver to intentionally not
let user know about the failed requests..

> IDE tape as one example, seems to have it's own system of passing
> errors back up to the special command completion, via rq->errors
> and IDE_DRV_ERROR_GENERAL.

Please look at the patch/code:

rq->errors = 0;
- ide_complete_rq(drive, 0, blk_rq_bytes(rq));
+ ide_complete_rq(drive, -EIO, blk_rq_bytes(rq));

and notice rq->errors line.

> See idetape_queue_rw_tail() and ide_tape_callback() for example.
>
> IDE floppy has similar pieces of logic, and possibly similar desires
> wrt. emission of the block layer I/O error log message during
> special requests.
>
> When something sticks out like an eyesore (as this -EIO thing does)
> and seems to make no sense at all, there often is some obscure
> reason.

The obscure reasons is just the fact that both ide-floppy and ide-tape
had a they own duplicated/buggy request completion routines.

While they were being unified the whole bunch of similar class of bugs
were fixed so I agree that there may still be more issues to deal with
there.