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Subject: Re: [PATCH] RDMA/mlx5: return the EFAULT per ibv_advise_mr(3)
To:     Jason Gunthorpe <jgg@nvidia.com>
CC:     Leon Romanovsky <leon@kernel.org>,
        "dledford@redhat.com" <dledford@redhat.com>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <20210801092050.6322-1-lizhijian@cn.fujitsu.com>
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 <fb1c7505-62d3-a64e-4c57-170f9f5f86a4@fujitsu.com>
From:   "Li, Zhijian" <lizhijian@cn.fujitsu.com>
Message-ID: <238e5d3c-30e8-86fc-0263-42864fd0d848@cn.fujitsu.com>
Date:   Sat, 28 Aug 2021 16:42:52 +0800
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Just noticed that there is another code path i was missing will return EINVAL
when get_prefetchable_mr returns NULL

ENOENT:
mlx5_ib_advise_mr_prefetch()
   -> mlx5_ib_prefetch_sg_list()
       -> get_prefetchable_mr()
    return -ENOENT;


EINVAL:
mlx5_ib_advise_mr_prefetch
   ->init_prefetch_work()
      -> get_prefetchable_mr()
     return -EINVAL;

where get_prefetchable_mr will check pd and write access & key
So which value we should return ?

Thanks
  

on 2021/8/26 9:18, Li, Zhijian wrote:
>
> On 26/08/2021 01:28, Jason Gunthorpe wrote:
>> On Sat, Aug 21, 2021 at 05:44:43PM +0800, Li, Zhijian wrote:
>>> convert to text and send again
>>>
>>>
>>> Hi Jason & Leon
>>>
>>> It reminds me that ibv_advise_mr doesn't mention ENOENT any more which value the API actually returns now.
>>> the ENOENT cases/situations returned by kernel mlx5 implementation is most likely same with EINVALL as its manpage[1].
>>>
>>> So shall we return EINVAL instead of ENOENT in kernel side when get_prefetchable_mr returns NULL?
>> No, the man page should be fixed
> thanks a lot, i have submitted a RP to rdma-core https://github.com/linux-rdma/rdma-core/pull/1048
>
> Thanks
> Zhijian
>
>> Jason
>>
>>