PCI: Don't attempt config access to disconnected devices

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If we've  detected the PCI device is disconnected, there is no need to
attempt to access its config space since we know the operation will fail.
Make all the config reads and writes return -ENODEV error immediately when
in such a state.

If a caller requests a config read to a disconnected device, return a data
value of all 1's.  This is the same as what hardware is expected to return
when accessing a removed device, but software can do this faster without
relying on hardware.

Tested-by: Krishna Dhulipala <krishnad@fb.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Wei Zhang <wzhang@fb.com>

...

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Keith Busch 2017-03-29 22:49:06 -05:00 • committed by Bjorn Helgaas

parent 89ee9f7680

commit 4b10388347

1 changed files with 18 additions and 0 deletions

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drivers/pci/access.c

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