diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2008-12-08 13:46:00 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-01-14 09:44:03 -0800 |
| commit | cf7af4a82fe408a8c9628480ac3dc272e087ce75 (patch) | |
| tree | 2bbcd39200e386232a266e39b0d9bda5d40bd674 /drivers/dma | |
| parent | 65e8fedf5e9d81cce3505a4dfce77096eac89711 (diff) | |
async_xor: dma_map destination DMA_BIDIRECTIONAL
commit a06d568f7c5e40e34ea64881842deb8f4382babf upstream.
Mapping the destination multiple times is a misuse of the dma-api.
Since the destination may be reused as a source, ensure that it is only
mapped once and that it is mapped bidirectionally. This appears to add
ugliness on the unmap side in that it always reads back the destination
address from the descriptor, but gcc can determine that dma_unmap is a
nop and not emit the code that calculates its arguments.
Cc: Saeed Bishara <saeed@marvell.com>
Acked-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/iop-adma.c | 16 | ||||
| -rw-r--r-- | drivers/dma/mv_xor.c | 15 |
2 files changed, 25 insertions, 6 deletions
diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c index 71fba82462cb..cbb7ab80a2fb 100644 --- a/drivers/dma/iop-adma.c +++ b/drivers/dma/iop-adma.c @@ -85,18 +85,28 @@ iop_adma_run_tx_complete_actions(struct iop_adma_desc_slot *desc, enum dma_ctrl_flags flags = desc->async_tx.flags; u32 src_cnt; dma_addr_t addr; + dma_addr_t dest; + src_cnt = unmap->unmap_src_cnt; + dest = iop_desc_get_dest_addr(unmap, iop_chan); if (!(flags & DMA_COMPL_SKIP_DEST_UNMAP)) { - addr = iop_desc_get_dest_addr(unmap, iop_chan); - dma_unmap_page(dev, addr, len, DMA_FROM_DEVICE); + enum dma_data_direction dir; + + if (src_cnt > 1) /* is xor? */ + dir = DMA_BIDIRECTIONAL; + else + dir = DMA_FROM_DEVICE; + + dma_unmap_page(dev, dest, len, dir); } if (!(flags & DMA_COMPL_SKIP_SRC_UNMAP)) { - src_cnt = unmap->unmap_src_cnt; while (src_cnt--) { addr = iop_desc_get_src_addr(unmap, iop_chan, src_cnt); + if (addr == dest) + continue; dma_unmap_page(dev, addr, len, DMA_TO_DEVICE); } diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c index 0328da020a10..bcda17426411 100644 --- a/drivers/dma/mv_xor.c +++ b/drivers/dma/mv_xor.c @@ -311,17 +311,26 @@ mv_xor_run_tx_complete_actions(struct mv_xor_desc_slot *desc, enum dma_ctrl_flags flags = desc->async_tx.flags; u32 src_cnt; dma_addr_t addr; + dma_addr_t dest; + src_cnt = unmap->unmap_src_cnt; + dest = mv_desc_get_dest_addr(unmap); if (!(flags & DMA_COMPL_SKIP_DEST_UNMAP)) { - addr = mv_desc_get_dest_addr(unmap); - dma_unmap_page(dev, addr, len, DMA_FROM_DEVICE); + enum dma_data_direction dir; + + if (src_cnt > 1) /* is xor ? */ + dir = DMA_BIDIRECTIONAL; + else + dir = DMA_FROM_DEVICE; + dma_unmap_page(dev, dest, len, dir); } if (!(flags & DMA_COMPL_SKIP_SRC_UNMAP)) { - src_cnt = unmap->unmap_src_cnt; while (src_cnt--) { addr = mv_desc_get_src_addr(unmap, src_cnt); + if (addr == dest) + continue; dma_unmap_page(dev, addr, len, DMA_TO_DEVICE); } |