linux-kernel - Re: [PATCH v4 09/15] pci: Consolidate pci_iomap* and pci

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Message-ID: <fbce6e80-07e3-8b95-dff6-1ade6be58b29@linux.intel.com>
Date:   Thu, 12 Aug 2021 15:29:42 -0700
From:   "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Richard Henderson <rth@...ddle.net>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        James E J Bottomley <James.Bottomley@...senPartnership.com>,
        Helge Deller <deller@....de>,
        "David S . Miller" <davem@...emloft.net>,
        Arnd Bergmann <arnd@...db.de>,
        Jonathan Corbet <corbet@....net>,
        "Michael S . Tsirkin" <mst@...hat.com>,
        Peter H Anvin <hpa@...or.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Tony Luck <tony.luck@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kirill Shutemov <kirill.shutemov@...ux.intel.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Kuppuswamy Sathyanarayanan <knsathya@...nel.org>,
        x86@...nel.org, linux-kernel@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-alpha@...r.kernel.org,
        linux-mips@...r.kernel.org, linux-parisc@...r.kernel.org,
        sparclinux@...r.kernel.org, linux-arch@...r.kernel.org,
        linux-doc@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH v4 09/15] pci: Consolidate pci_iomap* and pci_iomap*wc



On 8/12/21 12:43 PM, Bjorn Helgaas wrote:
> Is there a branch with all of this applied?  I was going to apply this

Its is maintained in following tree.

https://github.com/intel/tdx/commit/93fd5b655172ba9e3350487995102a8b2c41de27

> to help take a look at it, but it doesn't apply to v5.14-rc1.  I know

This patch can be applied independently. I have just applied it on top
of v5.14-rc5, and it seems to apply clean. Can you try -rc5?

> you listed some prereqs in the cover letter, but it's a fair amount of
> work to sort all that out.
> 
> On Wed, Aug 04, 2021 at 05:52:12PM -0700, Kuppuswamy Sathyanarayanan wrote:
>> From: Andi Kleen <ak@...ux.intel.com>
> 
> If I were applying these, I would silently update the subject lines to
> match previous commits.  Since these will probably be merged via a
> different tree, you can update if there's a v5:
> 
>    PCI: Consolidate pci_iomap_range(), pci_iomap_wc_range()

Yes. I will fix this in next version.

> 
> Also applies to 11/15 and 12/15.

Will do the same.

> 
>> pci_iomap* and pci_iomap*wc are currently duplicated code, except
>> that the _wc variant does not support IO ports. Replace them
>> with a common helper and a callback for the mapping. I used
>> wrappers for the maps because some architectures implement ioremap
>> and friends with macros.
> 
> Maybe spell some of this out:
> 
>    pci_iomap_range() and pci_iomap_wc_range() are currently duplicated
>    code, ...  Implement them using a common helper,
>    pci_iomap_range_map(), ...
> 
> Using "pci_iomap*" obscures the name and doesn't save any space.
> 
> Why is it safe to make pci_iomap_wc_range() support IO ports when it
> didn't before?  That might be desirable, but I think it *is* a
> functional change here.

Agree. Commit log had to be updated. I will include these details
in next submission.

> 
> IIUC, pci_iomap_wc_range() on an IO port range previously returned
> NULL, and after this patch it will work the same as pci_iomap_range(),
> i.e., it will return the result of __pci_ioport_map().
> 
>> This will allow to add more variants without excessive code
>> duplications. This patch should have no behavior change.
>>
>> Signed-off-by: Andi Kleen <ak@...ux.intel.com>
>> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
>> ---
>>   lib/pci_iomap.c | 81 +++++++++++++++++++++++++++----------------------
>>   1 file changed, 44 insertions(+), 37 deletions(-)
>>


-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer