From: Jason Gunthorpe <jgg@ziepe.ca>
To: Christoph Hellwig <hch@lst.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
Logan Gunthorpe <logang@deltatee.com>,
linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org,
iommu@lists.linux-foundation.org
Subject: Re: [PATCH 2/5] RDMA/core: remove use of dma_virt_ops
Date: Wed, 4 Nov 2020 09:42:41 -0400 [thread overview]
Message-ID: <20201104134241.GP36674@ziepe.ca> (raw)
In-Reply-To: <20201104095052.1222754-3-hch@lst.de>
On Wed, Nov 04, 2020 at 10:50:49AM +0100, Christoph Hellwig wrote:
> +int ib_dma_virt_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents)
> +{
> + struct scatterlist *s;
> + int i;
> +
> + for_each_sg(sg, s, nents, i) {
> + sg_dma_address(s) = (uintptr_t)sg_virt(s);
> + sg_dma_len(s) = s->length;
Hmm.. There is nothing ensuring the page is mapped here for this
sg_virt(). Before maybe some of the kconfig stuff prevented highmem
systems indirectly, I wonder if we should add something more direct to
exclude highmem for these drivers?
Sigh. I think the proper fix is to replace addr/length with a
scatterlist pointer in the struct ib_sge, then have SW drivers
directly use the page pointer properly.
Then just delete this stuff, all drivers need is a noop dmaops
Looks a lot hard though, so we should probably go ahead with this.
Jason
next prev parent reply other threads:[~2020-11-04 13:42 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-04 9:50 remove dma_virt_ops Christoph Hellwig
2020-11-04 9:50 ` [PATCH 1/5] RDMA/core: remove ib_dma_{alloc,free}_coherent Christoph Hellwig
2020-11-04 9:50 ` [PATCH 2/5] RDMA/core: remove use of dma_virt_ops Christoph Hellwig
2020-11-04 13:42 ` Jason Gunthorpe [this message]
2020-11-04 14:01 ` Christoph Hellwig
2020-11-04 15:09 ` Bernard Metzler
2020-11-04 18:10 ` Jason Gunthorpe
2020-11-04 15:52 ` Jason Gunthorpe
2020-11-04 16:31 ` Christoph Hellwig
2020-11-04 18:09 ` Jason Gunthorpe
2020-11-04 9:50 ` [PATCH 3/5] PCI/p2p: remove the DMA_VIRT_OPS hacks Christoph Hellwig
2020-11-04 16:53 ` Bjorn Helgaas
2020-11-04 17:00 ` Logan Gunthorpe
2020-11-04 9:50 ` [PATCH 4/5] PCI/p2p: cleanup up __pci_p2pdma_map_sg a bit Christoph Hellwig
2020-11-04 16:54 ` Bjorn Helgaas
2020-11-04 9:50 ` [PATCH 5/5] dma-mapping: remove dma_virt_ops Christoph Hellwig
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