On Mon, 20 Oct 2008 11:20:49 +0900 FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> wrote: > On Sat, 18 Oct 2008 20:07:47 +0200 > Borislav Petkov <petkovbb@xxxxxxxxxxxxxx> wrote: > > > would you please take a look at this bug caused by > > > > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff_plain;h=e5318b531b008c79d2a0c0df06a7b8628da38e2f > > Did he confirm that this patch causes this bug? > > But, yes, this patch might be the cause. > > Using the dma safe check for all the non fs commands is the right > thing. But blk_queue_update_dma_pad() has side effects. It might be > the cause (but I'm not sure about it since I don't know how the ide > code completes requests). > > IDE simply disables DMA for unaligned requests (unlike libata) so > there is no point to tell the block layer about the dma padding > limitation. > > Valerio, can you try this patch? > > Thanks, > > > diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c > index 3308b1c..6961877 100644 > --- a/drivers/ide/ide-cd.c > +++ b/drivers/ide/ide-cd.c > @@ -1250,7 +1250,7 @@ static void cdrom_do_block_pc(ide_drive_t *drive, struct request *rq) > * NOTE! The "len" and "addr" checks should possibly have > * separate masks. > */ > - alignment = queue_dma_alignment(q) | q->dma_pad_mask; > + alignment = queue_dma_alignment(q) | 15; > if ((unsigned long)buf & alignment || rq->data_len & alignment > || object_is_on_stack(buf)) > drive->dma = 0; > @@ -1981,7 +1981,6 @@ static int ide_cdrom_setup(ide_drive_t *drive) > > blk_queue_prep_rq(drive->queue, ide_cdrom_prep_fn); > blk_queue_dma_alignment(drive->queue, 31); > - blk_queue_update_dma_pad(drive->queue, 15); > drive->queue->unplug_delay = (1 * HZ) / 1000; > if (!drive->queue->unplug_delay) > drive->queue->unplug_delay = 1; Valerio told me that the above patch doesn't work however reverting the commit works for him. I think that the dma safe check for all the non fs commands is the right thing. And I thought false positive (that is, disabling dma even if a request is dma-capable) is fine here... Any ideas about what might be wrong? -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
