Re: [PATCH] RDMA/mlx5: return the EFAULT per ibv_advise_mr(3)

lizhijian
2021-08-16T03:06:45Z

On 05/08/2021 14:43, Leon Romanovsky wrote:
> On Wed, Aug 04, 2021 at 03:50:22PM -0300, Jason Gunthorpe wrote:
>> On Wed, Aug 04, 2021 at 08:35:30AM +0300, Leon Romanovsky wrote:
>>> On Tue, Aug 03, 2021 at 03:13:41PM -0300, Jason Gunthorpe wrote:
>>>> On Tue, Aug 03, 2021 at 08:56:54PM +0300, Leon Romanovsky wrote:
>>>>> On Tue, Aug 03, 2021 at 01:25:07PM -0300, Jason Gunthorpe wrote:
>>>>>> On Sun, Aug 01, 2021 at 05:20:50PM +0800, Li Zhijian wrote:
>>>>>>> ibv_advise_mr(3) says:
>>>>>>> EFAULT In one of the following: o When the range requested is out of the MR bounds,
>>>>>>> or when parts of it are not part of the process address space. o One of the
>>>>>>> lkeys provided in the scatter gather list is invalid or with wrong write access
>>>>>>>
>>>>>>> Actually get_prefetchable_mr() will return NULL if it see above conditions
>>>>>> No, get_prefetchable_mr() returns NULL if the mkey is invalid
>>>>> And what is this?
>>>>> 1701 static struct mlx5_ib_mr *
>>>>> 1702 get_prefetchable_mr(struct ib_pd *pd, enum ib_uverbs_advise_mr_advice advice,
>>>>> 1703 u32 lkey)
>>>>>
>>>>> ...
>>>>>
>>>>> 1721 /* prefetch with write-access must be supported by the MR */
>>>>> 1722 if (advice == IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH_WRITE &&
>>>>> 1723 !mr->umem->writable) {
>>>>> 1724 mr = NULL;
>>>>> 1725 goto end;
>>>>> 1726 }
>>>> I would say that is an invalid mkey
>>> I see it is as wrong write access.
>> It just means the man page is wrong
> ok, it can be a solution too.

It sounds good.  I will try to update the manpage ibv_advise_mr(3) instead.

Thanks
Zhijian