Messages in this thread | | | Date | Mon, 15 Nov 2021 10:15:07 -0800 | From | Christoph Hellwig <> | Subject | Re: [PATCH 02/11] driver core: Set DMA ownership during driver bind/unbind |
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On Mon, Nov 15, 2021 at 11:56:13AM -0400, Jason Gunthorpe wrote: > drivers/base/platform.c: .dma_configure = platform_dma_configure, > drivers/bus/fsl-mc/fsl-mc-bus.c: .dma_configure = fsl_mc_dma_configure, > drivers/pci/pci-driver.c: .dma_configure = pci_dma_configure, > drivers/gpu/host1x/bus.c: .dma_configure = host1x_dma_configure, > > Other than host1x they all work with VFIO. > > Also, there is no bus->dma_unconfigure() which would be needed to > restore the device as well. > > So, would you rather see duplicated code into the 4 drivers, and a new > bus op to 'unconfigure dma'
The tend to mostly call into common helpers eventually.
> > Or, a 'dev_configure_dma()' function that is roughly: > > if (dev->bus->dma_configure) { > ret = dev->bus->dma_configure(dev); > if (ret) > return ret; > if (!drv->suppress_auto_claim_dma_owner) { > ret = iommu_device_set_dma_owner(dev, DMA_OWNER_KERNEL, > NULL); > if (ret) > ret; > } > } > > And a pair'd undo.
But that seems like an even better idea to me. Even better with an early return and avoiding the pointless indentation.
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