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);
+}
+
static void complete_command_orb(struct sbp2_orb *base_orb,
struct sbp2_status *status)
{
@@ -1364,15 +1377,7 @@ static void complete_command_orb(struct
dma_unmap_single(device->card->device, orb->base.request_bus,
sizeof(orb->request), DMA_TO_DEVICE);
-
- if (scsi_sg_count(orb->cmd) > 0)
- dma_unmap_sg(device->card->device, scsi_sglist(orb->cmd),
- scsi_sg_count(orb->cmd),
- orb->cmd->sc_data_direction);
-
- if (orb->page_table_bus != 0)
- dma_unmap_single(device->card->device, orb->page_table_bus,
- sizeof(orb->page_table), DMA_TO_DEVICE);
+ sbp2_unmap_scatterlist(device->card->device, orb);
orb->cmd->result = result;
orb->done(orb->cmd);
@@ -1493,8 +1498,10 @@ static int sbp2_scsi_queuecommand(struct
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)) {
+ sbp2_unmap_scatterlist(device->card->device, orb);
goto out;
+ }
sbp2_send_orb(&orb->base, lu, lu->tgt->node_id, generation,
lu->command_block_agent_address + SBP2_ORB_POINTER);
--
Stefan Richter
-=====-==--= ---= ==-==
http://arcgraph.de/sr/
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