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    SubjectRe: [PATCH v2 3/3] asm-generic/io.h: Fix !CONFIG_GENERIC_IOMAP pci_iounmap() implementation
    On Wed, Sep 16, 2020 at 12:06:58PM +0100, Lorenzo Pieralisi wrote:
    > For arches that do not select CONFIG_GENERIC_IOMAP, the current
    > pci_iounmap() function does nothing causing obvious memory leaks
    > for mapped regions that are backed by MMIO physical space.
    >
    > In order to detect if a mapped pointer is IO vs MMIO, a check must made
    > available to the pci_iounmap() function so that it can actually detect
    > whether the pointer has to be unmapped.
    >
    > In configurations where CONFIG_HAS_IOPORT_MAP && !CONFIG_GENERIC_IOMAP,
    > a mapped port is detected using an ioport_map() stub defined in
    > asm-generic/io.h.
    >
    > Use the same logic to implement a stub (ie __pci_ioport_unmap()) that
    > detects if the passed in pointer in pci_iounmap() is IO vs MMIO to
    > iounmap conditionally and call it in pci_iounmap() fixing the issue.
    >
    > Leave __pci_ioport_unmap() as a NOP for all other config options.
    >
    > Reported-by: George Cherian <george.cherian@marvell.com>
    > Link: https://lore.kernel.org/lkml/20200905024811.74701-1-yangyingliang@huawei.com
    > Link: https://lore.kernel.org/lkml/20200824132046.3114383-1-george.cherian@marvell.com
    > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    > Cc: Arnd Bergmann <arnd@arndb.de>
    > Cc: George Cherian <george.cherian@marvell.com>
    > Cc: Will Deacon <will@kernel.org>
    > Cc: Bjorn Helgaas <bhelgaas@google.com>
    > Cc: Catalin Marinas <catalin.marinas@arm.com>
    > Cc: Yang Yingliang <yangyingliang@huawei.com>
    > ---
    > include/asm-generic/io.h | 39 +++++++++++++++++++++++++++------------
    > 1 file changed, 27 insertions(+), 12 deletions(-)

    This works for me. The only question I have is whether pci_iomap.h is
    better than io.h for __pci_ioport_unmap(). These headers are really
    confusing.

    Either way:

    Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

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