On 8/17/2022 8:14 AM, Don.Brace@xxxxxxxxxxxxx wrote:
I have created an md raid6 device and added crypto.
I have also enabled the ioat driver. (ioatdma)
Don, I've answer your question previously [1]. The ioatdma driver no
longer supports XOR/PQ offload so you are not going to get that support.
And also the Cascade Lake platform you are using does not officially
support that in hardware either. If you really want to try it, you'll
need to find a pre-Skylake Xeon machine and run it on a 4.x kernel.
[1]:
https://lore.kernel.org/dmaengine/725501fb-f559-2825-1533-4aca8177d87d@xxxxxxxxx/
The flow seems to be md/raid5:async_xor_offs() -> crypto/async_tx/async_xor.c:async_xor_off()
Here it attempts to obtain a dma_chan and dma device, but they are always NULL.
Some added debug messages.
async_xor_offs: async_xor - Starting called async_tx_find_channel chan=0000000000000000 device=0000000000000000
So, can the md driver utilize a DMA engine? I believe the answer is yes, but I am missing some setup steps?
I can get the dmatest driver to interface successfully.
I may not know enough about how this works to ask proper questions...
Thanks,
Don Brace
