Re: [PATCH for-next v2 2/2] RDMA/erdma: Support non-4K page size in doorbell allocation

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

On 3/14/23 7:31 PM, Cheng Xu wrote:
> 
> 
> On 3/14/23 6:23 PM, Leon Romanovsky wrote:
>> On Tue, Mar 07, 2023 at 06:29:24PM +0800, Cheng Xu wrote:
>>> Doorbell resources are exposed to userspace by mmap. The size unit of mmap
>>> is PAGE_SIZE, previous implementation can not work correctly if PAGE_SIZE
>>> is not 4K. We support non-4K page size in this commit.
>>
>> Why do you need this information in rdma-core?
>> Can you use sysconf(_SC_PAGESIZE) there to understand the page size like
>> other providers?
>>
> 
> I don't expose PAGE_SIZE to userspace in this patchset, but the *offset* in
> PAGE of the DBs:
> 
> diff --git a/include/uapi/rdma/erdma-abi.h b/include/uapi/rdma/erdma-abi.h
> index b7a0222f978f..57f8942a3c56 100644
> --- a/include/uapi/rdma/erdma-abi.h
> +++ b/include/uapi/rdma/erdma-abi.h
> @@ -40,10 +40,13 @@ struct erdma_uresp_alloc_ctx {
>  	__u32 dev_id;
>  	__u32 pad;
>  	__u32 sdb_type;
> -	__u32 sdb_offset;
> +	__u32 sdb_entid;
>  	__aligned_u64 sdb;
>  	__aligned_u64 rdb;
>  	__aligned_u64 cdb;
> +	__u32 sdb_off;
> +	__u32 rdb_off;
> +	__u32 cdb_off;
>  };
> 
> Our doorbell space is aligned to 4096
> 

Please ignore these two response. There is something wrong with my Thunderbird:
When I press ctrl + s, it send the email, not save it.

Sorry for this.

Cheng Xu

> 
> 
>> Thanks