async_tx: remove walk of tx->parent chain in dma_wait_for_async_tx

[safe/jmp/linux-2.6] / include / linux / async_tx.h

diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h
index 3d21a25..12a2efc 100644 (file)
--- a/include/linux/async_tx.h
+++ b/include/linux/async_tx.h
@@ -83,6 +83,24 @@ struct async_submit_ctl {
 
 #ifdef CONFIG_DMA_ENGINE
 #define async_tx_issue_pending_all dma_issue_pending_all
+
+/**
+ * async_tx_issue_pending - send pending descriptor to the hardware channel
+ * @tx: descriptor handle to retrieve hardware context
+ *
+ * Note: any dependent operations will have already been issued by
+ * async_tx_channel_switch, or (in the case of no channel switch) will
+ * be already pending on this channel.
+ */
+static inline void async_tx_issue_pending(struct dma_async_tx_descriptor *tx)
+{
+       if (likely(tx)) {
+               struct dma_chan *chan = tx->chan;
+               struct dma_device *dma = chan->device;
+
+               dma->device_issue_pending(chan);
+       }
+}
 #ifdef CONFIG_ARCH_HAS_ASYNC_TX_FIND_CHANNEL
 #include <asm/async_tx.h>
 #else
@@ -98,6 +116,11 @@ static inline void async_tx_issue_pending_all(void)
        do { } while (0);
 }
 
+static inline void async_tx_issue_pending(struct dma_async_tx_descriptor *tx)
+{
+       do { } while (0);
+}
+
 static inline struct dma_chan *
 async_tx_find_channel(struct async_submit_ctl *submit,
                      enum dma_transaction_type tx_type, struct page **dst,