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authorDan Williams <dan.j.williams@intel.com>2009-11-19 17:10:37 -0700
committerDan Williams <dan.j.williams@intel.com>2009-11-19 23:21:03 -0700
commit7b3cc2b1fc2066391e498f3387204908c4eced21 (patch)
tree8a2bc28955710c580201046d04843773cb7d87a1 /crypto/async_tx/async_xor.c
parent4499a24dec00e037da7d09caccad45e7594a9c19 (diff)
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async_tx: build-time toggling of async_{syndrome,xor}_val dma support
ioat3.2 does not support asynchronous error notifications which makes the driver experience latencies when non-zero pq validate results are expected. Provide a mechanism for turning off async_xor_val and async_syndrome_val via Kconfig. This approach is generally useful for any driver that specifies ASYNC_TX_DISABLE_CHANNEL_SWITCH and would like to force the async_tx api to fall back to the synchronous path for certain operations. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'crypto/async_tx/async_xor.c')
-rw-r--r--crypto/async_tx/async_xor.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
index 79182dcb91b..079ae8ca590 100644
--- 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;