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, 10 insertions, 10 deletions

diff --git a/crypto/async_tx/async_memset.c b/crypto/async_tx/async_memset.c
index 760972803958..0c94851cfd37 100644
--- a/crypto/async_tx/async_memset.c
+++ b/crypto/async_tx/async_memset.c
@@ -48,20 +48,20 @@ async_memset(struct page *dest, int val, unsigned int offset,
 {
         struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMSET);
         struct dma_device *device = chan ? chan->device : NULL;
-        int int_en = cb_fn ? 1 : 0;
-        struct dma_async_tx_descriptor *tx = device ?
-                device->device_prep_dma_memset(chan, val, len,
-                        int_en) : NULL;
+        struct dma_async_tx_descriptor *tx = NULL;
 
-        if (tx) { /* run the memset asynchronously */
-                dma_addr_t dma_addr;
+        if (device) {
+                dma_addr_t dma_dest;
 
-                pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len);
-
-                dma_addr = dma_map_page(device->dev, dest, offset, len,
+                dma_dest = dma_map_page(device->dev, dest, offset, len,
                                         DMA_FROM_DEVICE);
-                tx->tx_set_dest(dma_addr, tx, 0);
 
+                tx = device->device_prep_dma_memset(chan, dma_dest, val, len,
+                                                    cb_fn != NULL);
+        }
+
+        if (tx) {
+                pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len);
                 async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
         } else { /* run the memset synchronously */
                 void *dest_buf;