Re: OOPS: 2.5.1-pre8 - cdrecord + ide_scsi

[Jens Axboe]

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On Sun, Dec 09 2001, Jens Axboe wrote:
> > Ok works with DMA off, so I expect that this new error is due to my resent
> > memory upgrade (36 Hours ago) and the switch to using HIGHMEM(4GB)..
> > So am I to believe that DMA is a problem with HIGHMEM(4GB) enabled ?
> 
> No it's probably still an ide-scsi bug, I'm not suspecting your
> hardware. The reason I ask is because until -pre8 (since bio merge in
> -pre2), ide-scsi never used DMA even though it was set for the drive.

Ok finally had a chance to look some more at this -- it was a bit more
hairy than I had hoped. Please try this ide-scsi one liner, it should
cure it. (the bug fix is the bio->bi_vcnt = 1 change only)

-- 
Jens Axboe

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--- /opt/kernel/linux-2.5.1-pre9/drivers/scsi/ide-scsi.c	Tue Dec 11 05:01:51 2001
+++ linux/drivers/scsi/ide-scsi.c	Tue Dec 11 09:24:14 2001
@@ -261,7 +261,7 @@
 	ide_drive_t *drive = hwgroup->drive;
 	idescsi_scsi_t *scsi = drive->driver_data;
 	struct request *rq = hwgroup->rq;
-	idescsi_pc_t *pc = (idescsi_pc_t *) rq->buffer;
+	idescsi_pc_t *pc = (idescsi_pc_t *) rq->special;
 	int log = test_bit(IDESCSI_LOG_CMD, &scsi->log);
 	struct Scsi_Host *host;
 	u8 *scsi_buf;
@@ -464,7 +464,7 @@
 #endif /* IDESCSI_DEBUG_LOG */
 
 	if (rq->flags & REQ_SPECIAL) {
-		return idescsi_issue_pc (drive, (idescsi_pc_t *) rq->buffer);
+		return idescsi_issue_pc (drive, (idescsi_pc_t *) rq->special);
 	}
 	blk_dump_rq_flags(rq, "ide-scsi: unsup command");
 	idescsi_end_request (0,HWGROUP (drive));
@@ -662,6 +662,7 @@
 	if ((first_bh = bhp = bh = bio_alloc(GFP_ATOMIC, 1)) == NULL)
 		goto abort;
 	bio_init(bh);
+	bh->bi_vcnt = 1;
 	while (--count) {
 		if ((bh = bio_alloc(GFP_ATOMIC, 1)) == NULL)
 			goto abort;
@@ -802,7 +803,7 @@
 	}
 
 	ide_init_drive_cmd (rq);
-	rq->buffer = (char *) pc;
+	rq->special = (char *) pc;
 	rq->bio = idescsi_dma_bio (drive, pc);
 	rq->flags = REQ_SPECIAL;
 	spin_unlock(&cmd->host->host_lock);

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