From: Jason Gunthorpe <jgg@ziepe.ca>
To: Bart Van Assche <bvanassche@acm.org>
Cc: "Saleem, Shiraz" <shiraz.saleem@intel.com>,
Leon Romanovsky <leonro@mellanox.com>,
Doug Ledford <dledford@redhat.com>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
"Ruhl, Michael J" <michael.j.ruhl@intel.com>,
"Weiny, Ira" <ira.weiny@intel.com>,
Adit Ranadive <aditr@vmware.com>,
Gal Pressman <galpress@amazon.com>,
Selvin Xavier <selvin.xavier@broadcom.com>
Subject: Re: [PATCH 2/4] RDMA/core: Set DMA parameters correctly
Date: Tue, 22 Oct 2019 11:40:38 -0300 [thread overview]
Message-ID: <20191022144038.GA23952@ziepe.ca> (raw)
In-Reply-To: <4d1fb001-ead8-81ce-893e-1ff94214c389@acm.org>
On Mon, Oct 21, 2019 at 11:10:12AM -0700, Bart Van Assche wrote:
> > device->dma_device could be pointing to parent if the caller
> > did not provide dma_ops. So wont this update the parent device
> > dma params?
>
> That's correct, this will update the parent device DMA parameters.
>
> > Also do we want to ensure all callers device max_seg_sz
> > params >= threshold (=2G)? If so, perhaps we can do something
> > similar to vb2_dma_contig_set_max_seg_size()
> >
> > https://elixir.bootlin.com/linux/v5.4-rc2/source/drivers/media/common/videobuf2/videobuf2-dma-contig.c#L734
>
> It depends on what PCIe RDMA adapters support. If all PCIe RDMA adapters
> supported by the Linux kernel support max_segment_size >= 2G the above code
> is probably the easiest approach.
All drivers chop the sgls up into whatever size they support, unlike
block we don't need the dma mapper to produce sgls in specific formats.
Jason
next prev parent reply other threads:[~2019-10-22 14:40 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 2:10 [PATCH 0/4] Fixes related to the DMA max_segment_size parameter Bart Van Assche
2019-10-21 2:10 ` [PATCH 1/4] RDMA/core: Fix ib_dma_max_seg_size() Bart Van Assche
2019-10-21 14:09 ` Jason Gunthorpe
2019-10-21 15:03 ` Bart Van Assche
2019-10-21 15:27 ` Jason Gunthorpe
2019-10-21 15:56 ` Bart Van Assche
2019-10-21 2:10 ` [PATCH 2/4] RDMA/core: Set DMA parameters correctly Bart Van Assche
2019-10-21 14:10 ` Jason Gunthorpe
2019-10-21 16:26 ` Bart Van Assche
2019-10-21 17:44 ` Saleem, Shiraz
2019-10-21 18:10 ` Bart Van Assche
2019-10-21 20:32 ` Saleem, Shiraz
2019-10-22 14:40 ` Jason Gunthorpe [this message]
2019-10-22 22:11 ` Bart Van Assche
2019-10-21 2:10 ` [PATCH 3/4] rdma_rxe: Increase DMA max_segment_size parameter Bart Van Assche
2019-10-21 2:10 ` [PATCH 4/4] siw: " Bart Van Assche
2019-10-21 9:36 ` Bernard Metzler
2019-10-21 13:53 ` Bart Van Assche
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