From 7b3cc2b1fc2066391e498f3387204908c4eced21 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 19 Nov 2009 17:10:37 -0700 Subject: 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 --- crypto/async_tx/async_xor.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'crypto/async_tx/async_xor.c') 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; -- cgit v1.2.3