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Subject: Re: dynamic-sg patch has broken rdma_rxe
To:     Jason Gunthorpe <jgg@nvidia.com>,
        Bob Pearson <rpearsonhpe@gmail.com>,
        Leon Romanovsky <leonro@nvidia.com>,
        Christoph Hellwig <hch@lst.de>
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References: <0fdfc60e-ea93-8cf2-b23a-ce5d07d5fe33@gmail.com>
 <20201014225125.GC5316@nvidia.com>
From:   Maor Gottlieb <maorg@nvidia.com>
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Date:   Thu, 15 Oct 2020 10:44:44 +0300
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On 10/15/2020 1:51 AM, Jason Gunthorpe wrote:
> On Tue, Oct 13, 2020 at 09:33:14AM -0500, Bob Pearson wrote:
>> Jason,
>>
>> Just pulled for-next and now hit the following warning.
>> Register user space memory is not longer working.
>> I am trying to debug this but if you have any idea where to look let me =
know.
> The offset_in_page is wrong, but it is protecting some other logic..
>
> Maor? Leon? Can you sort it out tomorrow?

Leon and I investigated it. This check existed before my series to=20
protect the alloc_table_from_pages logic. It's still relevant.
This patch that broke it:=C2=A0 54816d3e69d1 ("RDMA: Explicitly pass in the=
=20
dma_device to ib_register_device"), and according to below link it was=20
expected.=C2=A0 The safest approach is to set the max_segment_size back the=
=20
2GB in all drivers. What do you think?

https://lore.kernel.org/linux-rdma/20200923072111.GA31828@infradead.org/

>
> Jason