[PATCH 28/29] dmaengine: kill tx_list

Dan Williams
2009-09-04T02:33:26Z

The tx_list attribute of struct dma_async_tx_descriptor is common to
most, but not all dma driver implementations. None of the upper level
code (dmaengine/async_tx) uses it, so allow drivers to implement it
locally if they need it. This saves sizeof(struct list_head) bytes for
drivers that do not manage descriptors with a linked list (e.g.: ioatdma
v2,3).

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/dma/dmaengine.c | 1 -
include/linux/dmaengine.h | 3 ---
2 files changed, 0 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 5a87384..562d182 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -933,7 +933,6 @@ void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
{
tx->chan = chan;
spin_lock_init(&tx->lock);
- INIT_LIST_HEAD(&tx->tx_list);
}
EXPORT_SYMBOL(dma_async_tx_descriptor_init);

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index ffefba8..f114bc7 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -180,8 +180,6 @@ typedef void (*dma_async_tx_callback)(void *dma_async_param);
* @flags: flags to augment operation preparation, control completion, and
* communicate status
* @phys: physical address of the descriptor
- * @tx_list: driver common field for operations that require multiple
- * descriptors
* @chan: target channel for this operation
* @tx_submit: set the prepared descriptor(s) to be executed by the engine
* @callback: routine to call after this operation is complete
@@ -195,7 +193,6 @@ struct dma_async_tx_descriptor {
dma_cookie_t cookie;
enum dma_ctrl_flags flags; /* not a 'long' to pack with cookie */
dma_addr_t phys;
- struct list_head tx_list;
struct dma_chan *chan;
dma_cookie_t (*tx_submit)(struct dma_async_tx_descriptor *tx);
dma_async_tx_callback callback;