From: David Woodhouse <dwmw2@infradead.org>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: linux-pci@vger.kernel.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/17] pci: Add arch_can_pci_mmap_wc() macro
Date: Wed, 05 Apr 2017 09:22:24 +0200 [thread overview]
Message-ID: <1491376944.22176.15.camel@infradead.org> (raw)
In-Reply-To: <20170404213631.GB989@bhelgaas-glaptop.roam.corp.google.com>
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On Tue, 2017-04-04 at 16:36 -0500, Bjorn Helgaas wrote:
> > --- a/arch/xtensa/kernel/pci.c
> > +++ b/arch/xtensa/kernel/pci.c
> > @@ -345,7 +345,7 @@ __pci_mmap_set_pgprot(struct pci_dev *dev, struct vm_area_struct *vma,
> >
> > /* Set to write-through */
> > prot = (prot & _PAGE_CA_MASK) | _PAGE_CA_WT;
> > -#if 0
> > +#ifdef arch_can_pci_mmap_wc
>
> This hunk seems like maybe it should be a separate patch.
>
> ...
>
> This part seems different -- it changes the way pci_mmap_page_range()
> works.
It doesn't, because arch_can_pci_map_wc isn't defined on xtensa. So
it's just a trivial cleanup for future-proofing, turning that 'if 0'
into 'if <something that isn't set>'.
> > diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
> > index dc8912e..c49be71 100644
> > --- a/drivers/pci/proc.c
> > +++ b/drivers/pci/proc.c
> > @@ -209,15 +209,18 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd,
> > fpriv->mmap_state = pci_mmap_mem;
> > break;
> >
> > +#ifdef arch_can_pci_mmap_wc
> Can we get rid of these #ifdefs in the code by adding this to linux/pci.h?
>
> #ifndef arch_can_pci_mmap_wc
> #define arch_can_pci_mmap_wc() 0
> #endif
Er.... at the time, that was non-trivial because there was something
that actually needed to be *removed* with the preprocessor instead of
just not being called. But after I settled on the incremental approach
of having pci_mmap_resource_range() be a wrapper for
pci_mmap_page_range() *and* vice versa I think that requirement went
away. I'll take another look and see if I can do that now; thanks.
Are you happy with the suggestion that we use HAVE_PCI_MMAP *only* to
control mmap on /proc/bus/pci, and we present mmap through sysfs on all
platforms via the generic code?
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next prev parent reply other threads:[~2017-04-05 7:22 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-22 13:25 [PATCH 00/17] PCI resource mmap cleanup David Woodhouse
2017-03-22 13:25 ` [PATCH 01/17] pci: Fix pci_mmap_fits() for HAVE_PCI_RESOURCE_TO_USER platforms David Woodhouse
2017-03-22 13:25 ` [PATCH 02/17] pci: Fix another sanity check bug in /proc/pci mmap David Woodhouse
2017-03-22 13:25 ` [PATCH 03/17] pci: Only allow WC mmap on prefetchable resources David Woodhouse
2017-03-24 16:05 ` Arnd Bergmann
2017-03-24 17:04 ` David Woodhouse
2017-03-22 13:25 ` [PATCH 04/17] pci: Add arch_can_pci_mmap_wc() macro David Woodhouse
2017-04-04 21:36 ` Bjorn Helgaas
2017-04-05 7:22 ` David Woodhouse [this message]
2017-03-22 13:25 ` [PATCH 05/17] pci: Move multiple declarations of pci_mmap_page_range() to <linux/pci.h> David Woodhouse
2017-03-22 13:25 ` [PATCH 06/17] pci: Add HAVE_PCI_MMAP_IO to architectures which can mmap() I/O space David Woodhouse
2017-03-22 13:25 ` [PATCH 07/17] pci: Use BAR index in sysfs attr->private instead of resource pointer David Woodhouse
2017-03-22 13:25 ` [PATCH 08/17] pci: Add BAR index argument to pci_mmap_page_range() David Woodhouse
2017-03-22 13:25 ` [PATCH 09/17] pci: Add pci_mmap_resource_range() and use it for ARM64 David Woodhouse
2017-03-22 13:25 ` [PATCH 10/17] arm: Use generic pci_mmap_resource_range() David Woodhouse
2017-03-22 13:25 ` [PATCH 11/17] cris: " David Woodhouse
2017-03-22 13:33 ` Jesper Nilsson
2017-03-22 13:25 ` [PATCH 12/17] mips: " David Woodhouse
2017-03-22 13:25 ` [PATCH 13/17] mn10300: " David Woodhouse
2017-03-22 13:25 ` [PATCH 14/17] parisc: " David Woodhouse
2017-03-22 13:25 ` [PATCH 15/17] sh: " David Woodhouse
2017-03-22 13:25 ` [PATCH 16/17] unicore: " David Woodhouse
2017-03-22 13:25 ` [PATCH 17/17] arm64: Do not expose PCI mmap through procfs David Woodhouse
2017-03-22 13:54 ` Sinan Kaya
2017-03-22 14:04 ` David Woodhouse
2017-03-22 14:15 ` Sinan Kaya
2017-03-22 14:18 ` Will Deacon
2017-03-22 15:40 ` Sinan Kaya
2017-03-24 16:13 ` Arnd Bergmann
2017-03-24 16:16 ` Arnd Bergmann
2017-03-24 16:23 ` David Woodhouse
2017-03-24 16:20 ` David Woodhouse
2017-03-23 14:29 ` [PATCH 18/17] x86: Use generic pci_mmap_resource_range() David Woodhouse
2017-03-24 11:40 ` [PATCH 00/17] PCI resource mmap cleanup David Woodhouse
2017-03-24 16:57 ` Luck, Tony
2017-03-24 16:20 ` Arnd Bergmann
2017-04-04 22:43 ` Bjorn Helgaas
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