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, 15 insertions, 24 deletions

diff --git a/drivers/dma/ioat_dma.c b/drivers/dma/ioat_dma.c
index 45e7b4666c7b..5bcfc55a2776 100644
--- a/drivers/dma/ioat_dma.c
+++ b/drivers/dma/ioat_dma.c
@@ -159,20 +159,6 @@ static int ioat_dma_enumerate_channels(struct ioatdma_device *device)
         return device->common.chancnt;
 }
 
-static void ioat_set_src(dma_addr_t addr,
-                         struct dma_async_tx_descriptor *tx,
-                         int index)
-{
-        tx_to_ioat_desc(tx)->src = addr;
-}
-
-static void ioat_set_dest(dma_addr_t addr,
-                          struct dma_async_tx_descriptor *tx,
-                          int index)
-{
-        tx_to_ioat_desc(tx)->dst = addr;
-}
-
 /**
  * ioat_dma_memcpy_issue_pending - push potentially unrecognized appended
  *                                 descriptors to hw
@@ -415,8 +401,6 @@ static struct ioat_desc_sw *ioat_dma_alloc_descriptor(
 
         memset(desc, 0, sizeof(*desc));
         dma_async_tx_descriptor_init(&desc_sw->async_tx, &ioat_chan->common);
-        desc_sw->async_tx.tx_set_src = ioat_set_src;
-        desc_sw->async_tx.tx_set_dest = ioat_set_dest;
         switch (ioat_chan->device->version) {
         case IOAT_VER_1_2:
                 desc_sw->async_tx.tx_submit = ioat1_tx_submit;
@@ -714,6 +698,8 @@ static struct ioat_desc_sw *ioat_dma_get_next_descriptor(
 
 static struct dma_async_tx_descriptor *ioat1_dma_prep_memcpy(
                                                 struct dma_chan *chan,
+                                                dma_addr_t dma_dest,
+                                                dma_addr_t dma_src,
                                                 size_t len,
                                                 int int_en)
 {
@@ -726,6 +712,8 @@ static struct dma_async_tx_descriptor *ioat1_dma_prep_memcpy(
 
         if (new) {
                 new->len = len;
+                new->dst = dma_dest;
+                new->src = dma_src;
                 return &new->async_tx;
         } else
                 return NULL;
@@ -733,6 +721,8 @@ static struct dma_async_tx_descriptor *ioat1_dma_prep_memcpy(
 
 static struct dma_async_tx_descriptor *ioat2_dma_prep_memcpy(
                                                 struct dma_chan *chan,
+                                                dma_addr_t dma_dest,
+                                                dma_addr_t dma_src,
                                                 size_t len,
                                                 int int_en)
 {
@@ -749,6 +739,8 @@ static struct dma_async_tx_descriptor *ioat2_dma_prep_memcpy(
 
         if (new) {
                 new->len = len;
+                new->dst = dma_dest;
+                new->src = dma_src;
                 return &new->async_tx;
         } else
                 return NULL;
@@ -1045,7 +1037,7 @@ static int ioat_dma_self_test(struct ioatdma_device *device)
         u8 *dest;
         struct dma_chan *dma_chan;
         struct dma_async_tx_descriptor *tx;
-        dma_addr_t addr;
+        dma_addr_t dma_dest, dma_src;
         dma_cookie_t cookie;
         int err = 0;
 
@@ -1073,7 +1065,12 @@ static int ioat_dma_self_test(struct ioatdma_device *device)
                 goto out;
         }
 
-        tx = device->common.device_prep_dma_memcpy(dma_chan, IOAT_TEST_SIZE, 0);
+        dma_src = dma_map_single(dma_chan->device->dev, src, IOAT_TEST_SIZE,
+                                 DMA_TO_DEVICE);
+        dma_dest = dma_map_single(dma_chan->device->dev, dest, IOAT_TEST_SIZE,
+                                  DMA_FROM_DEVICE);
+        tx = device->common.device_prep_dma_memcpy(dma_chan, dma_dest, dma_src,
+                                                   IOAT_TEST_SIZE, 0);
         if (!tx) {
                 dev_err(&device->pdev->dev,
                         "Self-test prep failed, disabling\n");
@@ -1082,12 +1079,6 @@ static int ioat_dma_self_test(struct ioatdma_device *device)
         }
 
         async_tx_ack(tx);
-        addr = dma_map_single(dma_chan->device->dev, src, IOAT_TEST_SIZE,
-                              DMA_TO_DEVICE);
-        tx->tx_set_src(addr, tx, 0);
-        addr = dma_map_single(dma_chan->device->dev, dest, IOAT_TEST_SIZE,
-                              DMA_FROM_DEVICE);
-        tx->tx_set_dest(addr, tx, 0);
         tx->callback = ioat_dma_test_callback;
         tx->callback_param = (void *)0x8086;
         cookie = tx->tx_submit(tx);