async_tx: build-time toggling of async_{syndrome,xor}_val dma support

[net-next-2.6.git] / crypto / async_tx / async_xor.c

diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
index 79182dcb91b797760579482176cb652c495263a8..079ae8ca590bf869fdeb475a1bf4bea7a563831e 100644 (file)
--- a/crypto/async_tx/async_xor.c
+++ b/crypto/async_tx/async_xor.c
@@ -234,6 +234,17 @@ static int page_is_zero(struct page *p, unsigned int offset, size_t len)
                memcmp(a, a + 4, len - 4) == 0);
 }
 
+static inline struct dma_chan *
+xor_val_chan(struct async_submit_ctl *submit, struct page *dest,
+                struct page **src_list, int src_cnt, size_t len)
+{
+       #ifdef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
+       return NULL;
+       #endif
+       return async_tx_find_channel(submit, DMA_XOR_VAL, &dest, 1, src_list,
+                                    src_cnt, len);
+}
+
 /**
  * async_xor_val - attempt a xor parity check with a dma engine.
  * @dest: destination page used if the xor is performed synchronously
@@ -255,9 +266,7 @@ async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
              int src_cnt, size_t len, enum sum_check_flags *result,
              struct async_submit_ctl *submit)
 {
-       struct dma_chan *chan = async_tx_find_channel(submit, DMA_XOR_VAL,
-                                                     &dest, 1, src_list,
-                                                     src_cnt, len);
+       struct dma_chan *chan = xor_val_chan(submit, dest, src_list, src_cnt, len);
        struct dma_device *device = chan ? chan->device : NULL;
        struct dma_async_tx_descriptor *tx = NULL;
        dma_addr_t *dma_src = NULL;