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Date:   Thu, 22 Sep 2022 07:58:15 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Sagi Grimberg <sagi@grimberg.me>
Cc:     Rishabh Bhatnagar <risbhat@amazon.com>,
        linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
        hch@lst.de, axboe@fb.com, kbusch@kernel.org, mbacco@amazon.com
Subject: Re: [PATCH] nvme-pci: Set min align mask before calculating
 max_hw_sectors
Message-ID: <20220922055815.GA27619@lst.de>
References: <20220920191932.22797-1-risbhat@amazon.com> <871c0e19-9272-e92b-28dc-a50ae705bba8@grimberg.me>
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On Wed, Sep 21, 2022 at 11:10:58AM +0300, Sagi Grimberg wrote:
>
>> If swiotlb is force enabled dma_max_mapping_size ends up calling
>> swiotlb_max_mapping_size which takes into account the min align
>> mask for the device.
>> Set the min align mask for nvme driver before calling
>> dma_max_mapping_size while calculating max hw sectors.
>
> Does this fix a specific bug? if so it needs a fixes tag so it can
> go to stable backports as well.

Hmm.  Basically this is another fixlet for nvme on swiotlb, which
already drove adding the max_mapping size and the align_mask, and
it seems we still hadn't covered all corner cases properly.  So
I think it basically has been broken since day 1, but nvme on
swiotlb only started becoming "interesting" with the trusted
hypervisor schemes.