async_tx: kill tx_set_src and tx_set_dest methods

The tx_set_src and tx_set_dest methods were originally implemented to allow
an array of addresses to be passed down from async_xor to the dmaengine
driver while minimizing stack overhead.  Removing these methods allows
drivers to have all transaction parameters available at 'prep' time, saves
two function pointers in struct dma_async_tx_descriptor, and reduces the
number of indirect branches..

A consequence of moving this data to the 'prep' routine is that
multi-source routines like async_xor need temporary storage to convert an
array of linear addresses into an array of dma addresses.  In order to keep
the same stack footprint of the previous implementation the input array is
reused as storage for the dma addresses.  This requires that
sizeof(dma_addr_t) be less than or equal to sizeof(void *).  As a
consequence CONFIG_DMADEVICES now depends on !CONFIG_HIGHMEM64G.  It also
requires that drivers be able to make descriptor resources available when
the 'prep' routine is polled.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Shannon Nelson <shannon.nelson@intel.com>

1 files changed, 8 insertions, 12 deletions

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 5c84bf897593..b0864f5b729d 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -209,8 +209,6 @@ typedef void (*dma_async_tx_callback)(void *dma_async_param);
  *      descriptors
  * @chan: target channel for this operation
  * @tx_submit: set the prepared descriptor(s) to be executed by the engine
- * @tx_set_dest: set a destination address in a hardware descriptor
- * @tx_set_src: set a source address in a hardware descriptor
  * @callback: routine to call after this operation is complete
  * @callback_param: general parameter to pass to the callback routine
  * ---async_tx api specific fields---
@@ -227,10 +225,6 @@ struct dma_async_tx_descriptor {
         struct list_head tx_list;
         struct dma_chan *chan;
         dma_cookie_t (*tx_submit)(struct dma_async_tx_descriptor *tx);
-        void (*tx_set_dest)(dma_addr_t addr,
-                struct dma_async_tx_descriptor *tx, int index);
-        void (*tx_set_src)(dma_addr_t addr,
-                struct dma_async_tx_descriptor *tx, int index);
         dma_async_tx_callback callback;
         void *callback_param;
         struct list_head depend_list;
@@ -279,15 +273,17 @@ struct dma_device {
         void (*device_free_chan_resources)(struct dma_chan *chan);
 
         struct dma_async_tx_descriptor *(*device_prep_dma_memcpy)(
-                struct dma_chan *chan, size_t len, int int_en);
+                struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+                size_t len, int int_en);
         struct dma_async_tx_descriptor *(*device_prep_dma_xor)(
-                struct dma_chan *chan, unsigned int src_cnt, size_t len,
-                int int_en);
+                struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
+                unsigned int src_cnt, size_t len, int int_en);
         struct dma_async_tx_descriptor *(*device_prep_dma_zero_sum)(
-                struct dma_chan *chan, unsigned int src_cnt, size_t len,
-                u32 *result, int int_en);
+                struct dma_chan *chan, dma_addr_t *src, unsigned int src_cnt,
+                size_t len, u32 *result, int int_en);
         struct dma_async_tx_descriptor *(*device_prep_dma_memset)(
-                struct dma_chan *chan, int value, size_t len, int int_en);
+                struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
+                int int_en);
         struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)(
                 struct dma_chan *chan);