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 <redacted>
Link: https://lore.kernel.org/lkml/20200905024811.74701-1-yangyingliang@huawei.com (local)
Link: https://lore.kernel.org/lkml/20200824132046.3114383-1-george.cherian@marvell.com (local)
Signed-off-by: Lorenzo Pieralisi <redacted>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: George Cherian <redacted>
Cc: Will Deacon <will@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yang Yingliang <redacted>
---
 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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