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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_pq.c
parent4499a24dec00e037da7d09caccad45e7594a9c19 (diff)
downloadlinux-7b3cc2b1fc2066391e498f3387204908c4eced21.tar.bz2
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_pq.c')
-rw-r--r--crypto/async_tx/async_pq.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index 6b5cc4fba59f..ec87f53d5059 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -240,6 +240,16 @@ async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
}
EXPORT_SYMBOL_GPL(async_gen_syndrome);
+static inline struct dma_chan *
+pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len)
+{
+ #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
+ return NULL;
+ #endif
+ return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks,
+ disks, len);
+}
+
/**
* async_syndrome_val - asynchronously validate a raid6 syndrome
* @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
@@ -260,9 +270,7 @@ async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
size_t len, enum sum_check_flags *pqres, struct page *spare,
struct async_submit_ctl *submit)
{
- struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ_VAL,
- NULL, 0, blocks, disks,
- len);
+ struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
struct dma_device *device = chan ? chan->device : NULL;
struct dma_async_tx_descriptor *tx;
unsigned char coefs[disks-2];