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Subject: Re: [PATCH v4 11/15] pci: Add pci_iomap_shared{,_range}
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     Dan Williams <dan.j.williams@intel.com>,
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From:   Andi Kleen <ak@linux.intel.com>
Message-ID: <3a88a255-a528-b00a-912b-e71198d5f58f@linux.intel.com>
Date:   Sun, 29 Aug 2021 22:11:46 -0700
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On 8/29/2021 3:26 PM, Michael S. Tsirkin wrote:
> On Sun, Aug 29, 2021 at 09:17:53AM -0700, Andi Kleen wrote:
>> Also I changing this single call really that bad? It's not that we changing
>> anything drastic here, just give the low level subsystem a better hint about
>> the intention. If you don't like the function name, could make it an
>> argument instead?
> My point however is that the API should say that the
> driver has been audited,

We have that status in the struct device. If you want to tie the ioremap 
to that we could define a ioremap_device() with a device argument and 
decide based on that.

Or we can add _audited to the name. ioremap_shared_audited?

> not that the mapping has been
> done in some special way. For example the mapping can be
> in some kind of wrapper, not directly in the driver.
> However you want the driver validated, not the wrapper.
>
> Here's an idea:


I don't think magic differences of API behavior based on some define are 
a good idea.  That's easy to miss.

That's a "COME FROM" in API design.

Also it wouldn't handle the case that a driver has both private and 
shared ioremaps, e.g. for BIOS structures.

And we've been avoiding that drivers can self declare auditing, we've 
been trying to have a separate centralized list so that it's easier to 
enforce and avoids any cut'n'paste mistakes.

-Andi