linux-kernel - Re: [PATCH 2/2] x86/pci: Clean up usage of X86_DEV_DMA

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Message-ID: <af8787f3bdd8f48e568ce421030b2b4415d79678.camel@intel.com>
Date:   Wed, 10 Apr 2019 22:03:59 +0000
From:   "Derrick, Jonathan" <jonathan.derrick@...el.com>
To:     "mingo@...nel.org" <mingo@...nel.org>,
        "helgaas@...nel.org" <helgaas@...nel.org>
CC:     "hch@....de" <hch@....de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "Busch, Keith" <keith.busch@...el.com>,
        "x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH 2/2] x86/pci: Clean up usage of X86_DEV_DMA_OPS

On Wed, 2019-04-10 at 16:45 -0500, Bjorn Helgaas wrote:
> [+cc Keith, Jonathan (VMD guys)]
> 
> I'm OK with this from a PCI perspective.  It would be nice if
> 
>   dma_domain_list
>   dma_domain_list_lock
>   add_dma_domain()
>   del_dma_domain()
>   set_dma_domain_ops()
> 
> could all be moved to vmd.c, since they're really only used there.
> 
> But we don't really have a good way to call host bridge-specific code
> like set_dma_domain_ops() except via pcibios_add_device().  Someday
> maybe pcibios_add_device() will become a host bridge method.
I think these could have been contained to vmd.c with the host bridge
add_device callback [1] but I can't seem to find whatever came about
that discussion

[1] https://marc.info/?l=linux-pci&m=153337765811720&w=2



Either way, this looks fine
Reviewed-by: Jon Derrick <jonathan.derrick@...el.com>


> 
> Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
> 
> 
> On Wed, Apr 10, 2019 at 10:16:17AM +0200, Ingo Molnar wrote:
> > (+Cc. Patch quoted below. Acked-by from an x86 perspective.)
> > 
> > * Christoph Hellwig <hch@....de> wrote:
> > 
> > > We have supported per-device dma_map_ops in generic code for a
> > > long
> > > time, and this symbol just guards the inclusion of the
> > > dma_map_ops
> > > registry used for vmd.  Stop enabling it for anything but vmd.
> > > 
> > > Signed-off-by: Christoph Hellwig <hch@....de>
> > > ---
> > >  arch/x86/Kconfig               | 3 ---
> > >  drivers/misc/mic/Kconfig       | 4 ++--
> > >  drivers/pci/controller/Kconfig | 1 +
> > >  drivers/pci/controller/vmd.c   | 7 -------
> > >  4 files changed, 3 insertions(+), 12 deletions(-)
> > > 
> > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > > index 38c62ff8a3f0..d8e2e6519a61 100644
> > > --- a/arch/x86/Kconfig
> > > +++ b/arch/x86/Kconfig
> > > @@ -28,7 +28,6 @@ config X86_64
> > >  	select MODULES_USE_ELF_RELA
> > >  	select NEED_DMA_MAP_STATE
> > >  	select SWIOTLB
> > > -	select X86_DEV_DMA_OPS
> > >  	select ARCH_HAS_SYSCALL_WRAPPER
> > >  
> > >  #
> > > @@ -703,7 +702,6 @@ config STA2X11
> > >  	bool "STA2X11 Companion Chip Support"
> > >  	depends on X86_32_NON_STANDARD && PCI
> > >  	select ARCH_HAS_PHYS_TO_DMA
> > > -	select X86_DEV_DMA_OPS
> > >  	select SWIOTLB
> > >  	select MFD_STA2X11
> > >  	select GPIOLIB
> > > @@ -2877,7 +2875,6 @@ config HAVE_ATOMIC_IOMAP
> > >  
> > >  config X86_DEV_DMA_OPS
> > >  	bool
> > > -	depends on X86_64 || STA2X11
> > >  
> > >  config HAVE_GENERIC_GUP
> > >  	def_bool y
> > > diff --git a/drivers/misc/mic/Kconfig b/drivers/misc/mic/Kconfig
> > > index 242dcee14689..6736f72cc14a 100644
> > > --- a/drivers/misc/mic/Kconfig
> > > +++ b/drivers/misc/mic/Kconfig
> > > @@ -4,7 +4,7 @@ comment "Intel MIC Bus Driver"
> > >  
> > >  config INTEL_MIC_BUS
> > >  	tristate "Intel MIC Bus Driver"
> > > -	depends on 64BIT && PCI && X86 && X86_DEV_DMA_OPS
> > > +	depends on 64BIT && PCI && X86
> > >  	help
> > >  	  This option is selected by any driver which registers a
> > >  	  device or driver on the MIC Bus, such as
> > > CONFIG_INTEL_MIC_HOST,
> > > @@ -21,7 +21,7 @@ comment "SCIF Bus Driver"
> > >  
> > >  config SCIF_BUS
> > >  	tristate "SCIF Bus Driver"
> > > -	depends on 64BIT && PCI && X86 && X86_DEV_DMA_OPS
> > > +	depends on 64BIT && PCI && X86
> > >  	help
> > >  	  This option is selected by any driver which registers a
> > >  	  device or driver on the SCIF Bus, such as
> > > CONFIG_INTEL_MIC_HOST
> > > diff --git a/drivers/pci/controller/Kconfig
> > > b/drivers/pci/controller/Kconfig
> > > index 6012f3059acd..011c57cae4b0 100644
> > > --- a/drivers/pci/controller/Kconfig
> > > +++ b/drivers/pci/controller/Kconfig
> > > @@ -267,6 +267,7 @@ config PCIE_TANGO_SMP8759
> > >  
> > >  config VMD
> > >  	depends on PCI_MSI && X86_64 && SRCU
> > > +	select X86_DEV_DMA_OPS
> > >  	tristate "Intel Volume Management Device Driver"
> > >  	---help---
> > >  	  Adds support for the Intel Volume Management Device (VMD).
> > > VMD is a
> > > diff --git a/drivers/pci/controller/vmd.c
> > > b/drivers/pci/controller/vmd.c
> > > index cf6816b55b5e..999a5509e57e 100644
> > > --- a/drivers/pci/controller/vmd.c
> > > +++ b/drivers/pci/controller/vmd.c
> > > @@ -95,10 +95,8 @@ struct vmd_dev {
> > >  	struct irq_domain	*irq_domain;
> > >  	struct pci_bus		*bus;
> > >  
> > > -#ifdef CONFIG_X86_DEV_DMA_OPS
> > >  	struct dma_map_ops	dma_ops;
> > >  	struct dma_domain	dma_domain;
> > > -#endif
> > >  };
> > >  
> > >  static inline struct vmd_dev *vmd_from_bus(struct pci_bus *bus)
> > > @@ -293,7 +291,6 @@ static struct msi_domain_info
> > > vmd_msi_domain_info = {
> > >  	.chip		= &vmd_msi_controller,
> > >  };
> > >  
> > > -#ifdef CONFIG_X86_DEV_DMA_OPS
> > >  /*
> > >   * VMD replaces the requester ID with its own.  DMA mappings for
> > > devices in a
> > >   * VMD domain need to be mapped for the VMD, not the device
> > > requiring
> > > @@ -438,10 +435,6 @@ static void vmd_setup_dma_ops(struct vmd_dev
> > > *vmd)
> > >  	add_dma_domain(domain);
> > >  }
> > >  #undef ASSIGN_VMD_DMA_OPS
> > > -#else
> > > -static void vmd_teardown_dma_ops(struct vmd_dev *vmd) {}
> > > -static void vmd_setup_dma_ops(struct vmd_dev *vmd) {}
> > > -#endif
> > >  
> > >  static char __iomem *vmd_cfg_addr(struct vmd_dev *vmd, struct
> > > pci_bus *bus,
> > >  				  unsigned int devfn, int reg, int len)
> > > -- 
> > > 2.20.1
> > > 

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