async_tx: trim dma_async_tx_descriptor in 'no channel switch' case

Saves 24 bytes per descriptor (64-bit) when the channel-switching
capabilities of async_tx are not required.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 9 insertions, 7 deletions

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index d18b5d069d7e..fcfe1a62ffa5 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -978,7 +978,9 @@ void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
         struct dma_chan *chan)
 {
         tx->chan = chan;
+        #ifndef CONFIG_ASYNC_TX_DISABLE_CHANNEL_SWITCH
         spin_lock_init(&tx->lock);
+        #endif
 }
 EXPORT_SYMBOL(dma_async_tx_descriptor_init);
 
@@ -1011,7 +1013,7 @@ EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
  */
 void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
 {
-        struct dma_async_tx_descriptor *dep = tx->next;
+        struct dma_async_tx_descriptor *dep = txd_next(tx);
         struct dma_async_tx_descriptor *dep_next;
         struct dma_chan *chan;
 
@@ -1019,7 +1021,7 @@ void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
                 return;
 
         /* we'll submit tx->next now, so clear the link */
-        tx->next = NULL;
+        txd_clear_next(tx);
         chan = dep->chan;
 
         /* keep submitting up until a channel switch is detected
@@ -1027,14 +1029,14 @@ void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
          * processing the interrupt from async_tx_channel_switch
          */
         for (; dep; dep = dep_next) {
-                spin_lock_bh(&dep->lock);
-                dep->parent = NULL;
-                dep_next = dep->next;
+                txd_lock(dep);
+                txd_clear_parent(dep);
+                dep_next = txd_next(dep);
                 if (dep_next && dep_next->chan == chan)
-                        dep->next = NULL; /* ->next will be submitted */
+                        txd_clear_next(dep); /* ->next will be submitted */
                 else
                         dep_next = NULL; /* submit current dep and terminate */
-                spin_unlock_bh(&dep->lock);
+                txd_unlock(dep);
 
                 dep->tx_submit(dep);
         }