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>
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 5903a88..b401dad 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -26,6 +26,8 @@
select DMA_ENGINE
select DCA
select ASYNC_TX_DISABLE_CHANNEL_SWITCH
+ select ASYNC_TX_DISABLE_PQ_VAL_DMA
+ select ASYNC_TX_DISABLE_XOR_VAL_DMA
help
Enable support for the Intel(R) I/OAT DMA engine present
in recent Intel Xeon chipsets.
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index b6442f0..8f99354 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -632,16 +632,22 @@
#if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
if (!dma_has_cap(DMA_XOR, device->cap_mask))
return false;
+
+ #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
return false;
#endif
+ #endif
#if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
if (!dma_has_cap(DMA_PQ, device->cap_mask))
return false;
+
+ #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
return false;
#endif
+ #endif
return true;
}
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index 252cf2d..189788f 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -1206,6 +1206,16 @@
device->timer_fn = ioat2_timer_event;
}
+ #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
+ dma_cap_clear(DMA_PQ_VAL, dma->cap_mask);
+ dma->device_prep_dma_pq_val = NULL;
+ #endif
+
+ #ifdef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
+ dma_cap_clear(DMA_XOR_VAL, dma->cap_mask);
+ dma->device_prep_dma_xor_val = NULL;
+ #endif
+
/* -= IOAT ver.3 workarounds =- */
/* Write CHANERRMSK_INT with 3E07h to mask out the errors
* that can cause stability issues for IOAT ver.3
