James Bottomley wrote: > On Tue, 2007-05-08 at 18:14 +0200, Jens Axboe wrote: >> On Tue, May 08 2007, Alan Cox wrote: >>> The CD-ROM layer doesn't bounce requests for old ISA controllers (and >>> nor should it). However they get injected into the SCSI layer via >>> sr_ioctl which also doesn't bounce them and SCSI then passes the buffer >>> along to a device with unchecked_isa_dma set which either panics or >>> truncates the buffer to 24bits. >>> >>> According to Jens the right long term fix is for the CD layer to route >>> the requests differently but in the mean time this has been tested by a >>> victim and verified to sort the problem out. For the other 99.9% of users >>> it's a no-op and doesn't bounce data. >>> >>> Signed-off-by: Alan Cox <alan@xxxxxxxxxx> >> Signed-off-by: Jens Axboe <jens.axboe@xxxxxxxxxx> >> >> Christoph passed me his patch to get rid of ->generic_packet() in the >> cdrom layer, so the work is almost complete. This patch is fine as a >> work-around until that gets merged, though. > > Actually, I think the new scsi request infrastructure should be doing > the bouncing (rather than have it done in each problem path we > discover). > > Mike Christie tells me we're missing bouncing by accident in the > scsi_execute path (but not the scsi_execute_async path). He says this > is the fix he proposed: > > http://marc.info/?l=linux-scsi&m=115981479822790&w=2 > Hey Jens and James, one thing I forgot to mention is that I could not remember if I needed an extra bio_get in there. I thought I did not because the caller is not touching the bio after the bio_endio calls like is done with the blk/bio_map_user path. But I did that patch so long ago I do not remember now. - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
