From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Helgaas Date: Fri, 14 Dec 2018 21:15:33 +0000 Subject: Re: [PATCH 13/15] ACPI / scan: Refactor _CCA enforcement Message-Id: <20181214211533.GE20725@google.com> List-Id: References: <20181207190720.18517-1-hch@lst.de> <20181207190720.18517-14-hch@lst.de> In-Reply-To: <20181207190720.18517-14-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Hellwig Cc: iommu@lists.linux-foundation.org, Linus Torvalds , Jesper Dangaard Brouer , Tariq Toukan , Ilias Apalodimas , Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= , Robin Murphy , Konrad Rzeszutek Wilk , Tony Luck , Fenghua Yu , Marek Szyprowski , Keith Busch , Jonathan Derrick , linux-pci@vger.kernel.org, linux-ia64@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org On Fri, Dec 07, 2018 at 11:07:18AM -0800, Christoph Hellwig wrote: > From: Robin Murphy > > Rather than checking the DMA attribute at each callsite, just pass it > through for acpi_dma_configure() to handle directly. That can then deal > with the relatively exceptional DEV_DMA_NOT_SUPPORTED case by explicitly > installing dummy DMA ops instead of just skipping setup entirely. This > will then free up the dev->dma_ops = NULL case for some valuable > fastpath optimisations. > > Signed-off-by: Robin Murphy > Signed-off-by: Christoph Hellwig > --- > drivers/acpi/scan.c | 5 +++++ > drivers/base/platform.c | 3 +-- > drivers/pci/pci-driver.c | 3 +-- Acked-by: Bjorn Helgaas # drivers/pci part > 3 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index bd1c59fb0e17..b75ae34ed188 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -1456,6 +1456,11 @@ int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) > const struct iommu_ops *iommu; > u64 dma_addr = 0, size = 0; > > + if (attr = DEV_DMA_NOT_SUPPORTED) { > + set_dma_ops(dev, &dma_dummy_ops); > + return 0; > + } > + > iort_dma_setup(dev, &dma_addr, &size); > > iommu = iort_iommu_configure(dev); > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index eae841935a45..c1ddf191711e 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -1138,8 +1138,7 @@ int platform_dma_configure(struct device *dev) > ret = of_dma_configure(dev, dev->of_node, true); > } else if (has_acpi_companion(dev)) { > attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode)); > - if (attr != DEV_DMA_NOT_SUPPORTED) > - ret = acpi_dma_configure(dev, attr); > + ret = acpi_dma_configure(dev, attr); > } > > return ret; > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > index bef17c3fca67..1b58e058b13f 100644 > --- a/drivers/pci/pci-driver.c > +++ b/drivers/pci/pci-driver.c > @@ -1602,8 +1602,7 @@ static int pci_dma_configure(struct device *dev) > struct acpi_device *adev = to_acpi_device_node(bridge->fwnode); > enum dev_dma_attr attr = acpi_get_dma_attr(adev); > > - if (attr != DEV_DMA_NOT_SUPPORTED) > - ret = acpi_dma_configure(dev, attr); > + ret = acpi_dma_configure(dev, acpi_get_dma_attr(adev)); > } > > pci_put_host_bridge_device(bridge); > -- > 2.19.1 >