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firewire: fw-sbp2: fix DMA mapping of S/G tables

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- The CPU must not touch the buffer after it was DMA-mapped.
  - The size argument of dma_unmap_single(...page_table...) was bogus.
  - Move a comment closer to the code to which it refers to.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
This commit is contained in:
Stefan Richter 2007-07-02 22:07:34 +02:00
parent 332ef3310b
commit b4be016ad8
1 changed files with 8 additions and 11 deletions
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19
drivers/firewire/fw-sbp2.c
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@ -887,7 +887,7 @@ complete_command_orb(struct sbp2_orb *base_orb, struct sbp2_status *status)
if (orb->page_table_bus != 0)
dma_unmap_single(device->card->device, orb->page_table_bus,
sizeof(orb->page_table_bus), DMA_TO_DEVICE);
sizeof(orb->page_table), DMA_TO_DEVICE);
orb->cmd->result = result;
orb->done(orb->cmd);
@ -902,7 +902,6 @@ static int sbp2_command_orb_map_scatterlist(struct sbp2_command_orb *orb)
struct fw_device *device = fw_device(unit->device.parent);
struct scatterlist *sg;
int sg_len, l, i, j, count;
size_t size;
dma_addr_t sg_addr;
sg = (struct scatterlist *)orb->cmd->request_buffer;
@ -951,7 +950,13 @@ static int sbp2_command_orb_map_scatterlist(struct sbp2_command_orb *orb)
}
}
size = sizeof(orb->page_table[0]) * j;
fw_memcpy_to_be32(orb->page_table, orb->page_table,
sizeof(orb->page_table[0]) * j);
orb->page_table_bus =
dma_map_single(device->card->device, orb->page_table,
sizeof(orb->page_table), DMA_TO_DEVICE);
if (dma_mapping_error(orb->page_table_bus))
goto fail_page_table;
/*
* The data_descriptor pointer is the one case where we need
@ -960,20 +965,12 @@ static int sbp2_command_orb_map_scatterlist(struct sbp2_command_orb *orb)
* initiator (i.e. us), but data_descriptor can refer to data
* on other nodes so we need to put our ID in descriptor.high.
*/
orb->page_table_bus =
dma_map_single(device->card->device, orb->page_table,
size, DMA_TO_DEVICE);
if (dma_mapping_error(orb->page_table_bus))
goto fail_page_table;
orb->request.data_descriptor.high = sd->address_high;
orb->request.data_descriptor.low = orb->page_table_bus;
orb->request.misc |=
COMMAND_ORB_PAGE_TABLE_PRESENT |
COMMAND_ORB_DATA_SIZE(j);
fw_memcpy_to_be32(orb->page_table, orb->page_table, size);
return 0;
fail_page_table: