async_tx: kill ASYNC_TX_DEP_ACK flag

In support of inter-channel chaining async_tx utilizes an ack flag to
gate whether a dependent operation can be chained to another.  While the
flag is not set the chain can be considered open for appending.  Setting
the ack flag closes the chain and flags the descriptor for garbage
collection.  The ASYNC_TX_DEP_ACK flag essentially means "close the
chain after adding this dependency".  Since each operation can only have
one child the api now implicitly sets the ack flag at dependency
submission time.  This removes an unnecessary management burden from
clients of the api.

[ Impact: clean up and enforce one dependency per operation ]

Reviewed-by: Andre Noll <maan@systemlinux.org>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

crypto/async_tx/async_memcpy.c

@@ -35,7 +35,7 @@
  * @src: src page
  * @offset: offset in pages to start transaction
  * @len: length in bytes
- * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK,
+ * @flags: ASYNC_TX_ACK
  * @depend_tx: memcpy depends on the result of this transaction
  * @cb_fn: function to call when the memcpy completes
  * @cb_param: parameter to pass to the callback routine

crypto/async_tx/async_memset.c

@@ -35,7 +35,7 @@
  * @val: fill value
  * @offset: offset in pages to start transaction
  * @len: length in bytes
- * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
+ * @flags: ASYNC_TX_ACK
  * @depend_tx: memset depends on the result of this transaction
  * @cb_fn: function to call when the memcpy completes
  * @cb_param: parameter to pass to the callback routine

crypto/async_tx/async_tx.c

@@ -223,7 +223,7 @@ async_tx_submit(struct dma_chan *chan, struct dma_async_tx_descriptor *tx,
 	if (flags & ASYNC_TX_ACK)
 		async_tx_ack(tx);
 
-	if (depend_tx && (flags & ASYNC_TX_DEP_ACK))
+	if (depend_tx)
 		async_tx_ack(depend_tx);
 }
 EXPORT_SYMBOL_GPL(async_tx_submit);
@@ -231,7 +231,7 @@ EXPORT_SYMBOL_GPL(async_tx_submit);
 /**
  * async_trigger_callback - schedules the callback function to be run after
  * any dependent operations have been completed.
- * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
+ * @flags: ASYNC_TX_ACK
  * @depend_tx: 'callback' requires the completion of this transaction
  * @cb_fn: function to call after depend_tx completes
  * @cb_param: parameter to pass to the callback routine

crypto/async_tx/async_xor.c

@@ -105,7 +105,6 @@ do_async_xor(struct dma_chan *chan, struct page *dest, struct page **src_list,
 				_cb_param);
 
 		depend_tx = tx;
-		flags |= ASYNC_TX_DEP_ACK;
 
 		if (src_cnt > xor_src_cnt) {
 			/* drop completed sources */
@@ -168,8 +167,7 @@ do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
  * @offset: offset in pages to start transaction
  * @src_cnt: number of source pages
  * @len: length in bytes
- * @flags: ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DEST,
- *	ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
+ * @flags: ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DEST, ASYNC_TX_ACK
  * @depend_tx: xor depends on the result of this transaction.
  * @cb_fn: function to call when the xor completes
  * @cb_param: parameter to pass to the callback routine
@@ -230,7 +228,7 @@ static int page_is_zero(struct page *p, unsigned int offset, size_t len)
  * @src_cnt: number of source pages
  * @len: length in bytes
  * @result: 0 if sum == 0 else non-zero
- * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
+ * @flags: ASYNC_TX_ACK
  * @depend_tx: xor depends on the result of this transaction.
  * @cb_fn: function to call when the xor completes
  * @cb_param: parameter to pass to the callback routine