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Date:   Thu, 6 Jun 2019 08:24:41 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Sebastian Ott <sebott@linux.ibm.com>,
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Subject: Re: [PATCH 08/13] IB/iser: set virt_boundary_mask in the scsi host
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References: <20190605190836.32354-1-hch@lst.de> <20190605190836.32354-9-hch@lst.de> <20190605202235.GC3273@ziepe.ca>
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On Wed, Jun 05, 2019 at 05:22:35PM -0300, Jason Gunthorpe wrote:
> On Wed, Jun 05, 2019 at 09:08:31PM +0200, Christoph Hellwig wrote:
> > This ensures all proper DMA layer handling is taken care of by the
> > SCSI midlayer.
> 
> Maybe not entirely related to this series, but it looks like the SCSI
> layer is changing the device global dma_set_max_seg_size() - at least
> in RDMA the dma device is being shared between many users, so we
> really don't want SCSI to make this value smaller.
> 
> Can we do something about this?

We could do something about it as outlined in my mail - pass the
dma_params explicitly to the dma_map_sg call.  But that isn't really
suitable for a short term fix and will take a little more time.

Until we've sorted that out the device paramter needs to be set to
the smallest value supported.