Re: [PATCH for-next v7 12/12] RDMA/erdma: Add driver to kernel build environment

[Cheng Xu <chengyou@linux.alibaba.com>]

On 5/16/22 10:13 PM, Jason Gunthorpe wrote:
> On Mon, May 16, 2022 at 11:40:46AM +0800, Cheng Xu wrote:
> 
>>>> diff --git a/drivers/infiniband/hw/Makefile b/drivers/infiniband/hw/Makefile
>>>> index fba0b3be903e..6b3a88046125 100644
>>>> +++ b/drivers/infiniband/hw/Makefile
>>>> @@ -13,3 +13,4 @@ obj-$(CONFIG_INFINIBAND_HFI1)		+= hfi1/
>>>>    obj-$(CONFIG_INFINIBAND_HNS)		+= hns/
>>>>    obj-$(CONFIG_INFINIBAND_QEDR)		+= qedr/
>>>>    obj-$(CONFIG_INFINIBAND_BNXT_RE)	+= bnxt_re/
>>>> +obj-$(CONFIG_INFINIBAND_ERDMA)		+= erdma/
>>>> diff --git a/drivers/infiniband/hw/erdma/Kconfig b/drivers/infiniband/hw/erdma/Kconfig
>>>> new file mode 100644
>>>> index 000000000000..c90f2be1ea63
>>>> +++ b/drivers/infiniband/hw/erdma/Kconfig
>>>> @@ -0,0 +1,12 @@
>>>> +# SPDX-License-Identifier: GPL-2.0-only
>>>> +config INFINIBAND_ERDMA
>>>> +	tristate "Alibaba Elastic RDMA Adapter (ERDMA) support"
>>>> +	depends on PCI_MSI && 64BIT && !CPU_BIG_ENDIAN
>>>
>>> Why !CPU_BIG_ENDIAN? That is usually not OK.
>>
>> we want use !CPU_BIG_ENDIAN to disable the erdma compilation on big
>> endian machine
> 
> Do not copy this
> 
>> because we only have little endian machines, and don't support big
>> endian machines. I have no idea why it is usually not OK, could you
>> explain it any more?
> 
> It is considered bad coding practice in the kernel. Write the required endian
> swaps.

Get it. Thanks.

Cheng Xu