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Date:   Fri, 30 Oct 2020 16:01:15 +0100
From:   "hch@lst.de" <hch@lst.de>
To:     Parav Pandit <parav@nvidia.com>
Cc:     Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
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Subject: Re: [PATCH] RDMA: Fix software RDMA drivers for dma mapping error
Message-ID: <20201030150115.GA15733@lst.de>
References: <20201030093803.278830-1-parav@nvidia.com> <20201030121731.GA36674@ziepe.ca> <71c2013a-e9af-470c-9fae-30fc0cf78ee3@cornelisnetworks.com> <BY5PR12MB43221AFDF37580F944C13967DC150@BY5PR12MB4322.namprd12.prod.outlook.com>
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On Fri, Oct 30, 2020 at 12:45:45PM +0000, Parav Pandit wrote:
> Christoph did say 64-bit good enough, but he mentioned that it is not correct on 32-bit platforms.
> So it is only for theoretical correctness.
> 
> > Technically there isn't. We are already dependent on 64bit config anyway.
> > Mike M just brought this up in a side bar conversation actually.
> For rvt driver, I should drop the check and always set to 64-bit.

Strictly speaking a dma_addr_t that is just the kernel virtual address
will never be larger than 32-bit on a 32-bit platform (by definition).
But setting it to 64 is entirely harmless, as we can't generate a larger
one (also by definition).