Re: Can't find CDR device in -mm only

[Jens Axboe <axboe@suse.de>]

On Sat, May 10 2003, Jens Axboe wrote:
> On Sat, May 10 2003, Shane Shrybman wrote:
> > Hi Jens,
> > 
> > On Sat, 2003-05-10 at 05:20, Jens Axboe wrote:
> > > On Fri, May 09 2003, Shane Shrybman wrote:
> > > > Hi,
> > > > 
> > > > The problem first appeared in 2.5.68-mm3 and is not in mainline 2.5.69.
> > > > It is present in all -mm releases since.
> > > 
> > > Curious. Looking at patches between .68-mm2 and -mm3 reveals nothing
> > > major, in fact the only thing touching anything in that area seems to be
> > > the dynamic request allocation patch. Could you try 2.5.69 with the
> > > attached patch to verify that it still works (or doesn't)? There might
> > > be a small offset in deadline-iosched.c, should be nothing to worry
> > > about.
> > 
> > Still doesn't work with 2.5.69 + rq_dyn. The output from cdrecord is
> > below.
> 
> Ah thanks, that kind of narrows it down then. I'll take a look at the
> problem tomorrow, should be easy to reproduce. Thanks for reporting!

Please try this patch, it should fix the issue for you. The reason is
that the RW bit is set from get_request() now, and scsi_ioctl always
uses WRITE as arguement to the function. So every request would be
turned into a write, oops :)

===== drivers/block/scsi_ioctl.c 1.25 vs edited =====
--- 1.25/drivers/block/scsi_ioctl.c	Tue Apr 29 13:41:31 2003
+++ edited/drivers/block/scsi_ioctl.c	Wed May 14 09:42:19 2003
@@ -229,6 +229,8 @@
 	rq->flags |= REQ_BLOCK_PC;
 	if (writing)
 		rq->flags |= REQ_RW;
+	else
+		rq->flags &= ~REQ_RW;
 
 	rq->hard_nr_sectors = rq->nr_sectors = nr_sectors;
 	rq->hard_cur_sectors = rq->current_nr_sectors = nr_sectors;
@@ -375,6 +377,8 @@
 	rq->flags |= REQ_BLOCK_PC;
 	if (in_len)
 		rq->flags |= REQ_RW;
+	else
+		rq->flags &= ~REQ_RW;
 
 	blk_do_rq(q, bdev, rq);
 	err = rq->errors & 0xff;	/* only 8 bit SCSI status */

-- 
Jens Axboe