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Date:   Mon, 04 Dec 2023 15:29:07 +0100
From:   "Arnd Bergmann" <arnd@arndb.de>
To:     "Philipp Stanner" <pstanner@redhat.com>,
        "Bjorn Helgaas" <bhelgaas@google.com>,
        "Hanjun Guo" <guohanjun@huawei.com>, "Neil Brown" <neilb@suse.de>,
        "Kent Overstreet" <kent.overstreet@gmail.com>,
        "Jakub Kicinski" <kuba@kernel.org>,
        "Niklas Schnelle" <schnelle@linux.ibm.com>,
        "Uladzislau Koshchanka" <koshchanka@gmail.com>,
        "John Sanpe" <sanpeqf@gmail.com>,
        "Dave Jiang" <dave.jiang@intel.com>,
        "Masami Hiramatsu" <mhiramat@kernel.org>,
        "Kees Cook" <keescook@chromium.org>,
        "David Gow" <davidgow@google.com>,
        "Herbert Xu" <herbert@gondor.apana.org.au>,
        "Shuah Khan" <skhan@linuxfoundation.org>,
        "wuqiang.matt" <wuqiang.matt@bytedance.com>,
        "Yury Norov" <yury.norov@gmail.com>,
        "Jason Baron" <jbaron@akamai.com>,
        "Andrew Morton" <akpm@linux-foundation.org>,
        "Ben Dooks" <ben.dooks@codethink.co.uk>,
        "Danilo Krummrich" <dakr@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
        Linux-Arch <linux-arch@vger.kernel.org>, stable@vger.kernel.org,
        "Arnd Bergmann" <arnd@kernel.org>
Subject: Re: [PATCH v3 5/5] lib, pci: unify generic pci_iounmap()
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On Mon, Dec 4, 2023, at 15:09, Philipp Stanner wrote:
> On Mon, 2023-12-04 at 14:50 +0100, Arnd Bergmann wrote:
>> On Mon, Dec 4, 2023, at 14:39, Philipp Stanner wrote:
>> > On Mon, 2023-12-04 at 13:38 +0100, Philipp Stanner wrote:
>
> Ok, makes sense.
>
> But should we then adjust iomem_is_ioport() in asm-generic/io.h, as
> well, so that it matches IO_COND()'s behavior?
>
> It currently does this:
>
> 	uintptr_t start = (uintptr_t)PCI_IOBASE;
> 	uintptr_t addr = (uintptr_t)addr_raw;
>
> 	if (addr >= start && addr < start + IO_SPACE_LIMIT)
> 		return true;
>
> and if the architecture does not set PCI_IOBASE, then it's set per
> default to 0, as well.
>
> So we have two inconsistent definitons

No, I would also keep the logic here, since it makes more sense
and the inconsistency is only for the corner case that doesn't
hit in practice.

The PCI_IOBASE==0 case should never happen here, as that doesn't
work with the generic inb(). I think the only target left that
has I/O ports but doesn't set PCI_IOBASE at all is sparc, but
that is special in a number of ways. 

     Arnd