On Tue, 27 Jan 2009 18:03:40 +0100 (CET)
Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx> wrote:
> On 27 Jan, FUJITA Tomonori wrote at LSML and LKML:
> [I wrote]
> >> > *) The report does not sound like there was a DMA mappig leak caused by
> >> > copying between usb-storage and firewire-sbp2. Else he would have hit
> >> > the problem again even with increased swiotlb default size.
>
> > Hmm, we don't have leak here?
> >
> > =
> > From: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
> > Subject: [PATCH] fw-sbp2: fix dma mapping leak on the failure path
> >
> > Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
> > ---
> > drivers/firewire/fw-sbp2.c | 12 +++++++++++-
> > 1 files changed, 11 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c
> > index e88d506..d40910d 100644
> > --- a/drivers/firewire/fw-sbp2.c
> > +++ b/drivers/firewire/fw-sbp2.c
> > @@ -1491,8 +1491,18 @@ static int sbp2_scsi_queuecommand(struct scsi_cmnd *cmd, scsi_done_fn_t done)
> > orb->base.request_bus =
> > dma_map_single(device->card->device, &orb->request,
> > sizeof(orb->request), DMA_TO_DEVICE);
> > - if (dma_mapping_error(device->card->device, orb->base.request_bus))
> > + if (dma_mapping_error(device->card->device, orb->base.request_bus)) {
> > + if (scsi_sg_count(cmd)) {
> > + dma_unmap_sg(device->card->device, scsi_sglist(cmd),
> > + scsi_sg_count(cmd),
> > + cmd->sc_data_direction);
> > + dma_unmap_single(device->card->device,
> > + orb->page_table_bus,
> > + sizeof(orb->page_table),
> > + DMA_TO_DEVICE);
> > + }
> > goto out;
> > + }
> >
> > sbp2_send_orb(&orb->base, lu, lu->tgt->node_id, generation,
> > lu->command_block_agent_address + SBP2_ORB_POINTER);
>
> Yes, we do have a leak there. Thanks a lot for checking the code.
>
> There is one thing missing in the fix: Even with scsi_sg_count(cmd) !=
> 0, there is sometimes no orb->page_table to unmap. It's when the
> scatterlist was mapped into a single physical segment.
>
>
> From: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
> Subject: firewire: sbp2: fix DMA mapping leak on the failure path
>
> Reported-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
> who also provided a first version of the fix.
>
> Signed-off-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
> ---
> drivers/firewire/fw-sbp2.c | 27 +++++++++++++++++----------
> 1 file changed, 17 insertions(+), 10 deletions(-)
>
> Index: linux/drivers/firewire/fw-sbp2.c
> ===================================================================
> --- linux.orig/drivers/firewire/fw-sbp2.c
> +++ linux/drivers/firewire/fw-sbp2.c
> @@ -1323,6 +1323,19 @@ static unsigned int sbp2_status_to_sense
> }
> }
>
> +static void sbp2_unmap_scatterlist(struct device *card_device,
> + struct sbp2_command_orb *orb)
> +{
> + if (scsi_sg_count(orb->cmd))
> + dma_unmap_sg(card_device, scsi_sglist(orb->cmd),
> + scsi_sg_count(orb->cmd),
> + orb->cmd->sc_data_direction);
> +
> + if (orb->page_table_bus)
> + dma_unmap_single(card_device, orb->page_table_bus,
> + sizeof(orb->page_table), DMA_TO_DEVICE);
Well, this does not look correct since zero can be a valid dma
address.
static void sbp2_unmap_scatterlist(struct device *card_device,
struct sbp2_command_orb *orb)
{
if (scsi_sg_count(orb->cmd))
dma_unmap_sg(card_device, scsi_sglist(orb->cmd),
scsi_sg_count(orb->cmd),
orb->cmd->sc_data_direction);
if (scsi_sg_count(orb->cmd) > 1)
dma_unmap_single(card_device, orb->page_table_bus,
sizeof(orb->page_table), DMA_TO_DEVICE);
Well, looks cranky a bit but firewire is cranky for me :)
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