[ Upstream commit 903534fa7d30214d8ba840ab1cd9e917e0c88e41 ]
pbus_size_mem() keeps the size of the optional resources in
children_add_size. When calculating the PCI bridge window size,
calculate_memsize() lower bounds size by old_size before adding
children_add_size and performing the window size alignment. This
results in double counting for the resources in children_add_size
because old_size may be based on the previous size of the bridge
window after it has already included children_add_size (that is,
size1 in pbus_size_mem() from an earlier invocation of that
function).
As a result, on repeated remove of the bus & rescan cycles the resource
size keeps increasing when children_add_size is non-zero as can be seen
from this extract:
iomem0: 23fffd00000-23fffdfffff : PCI Bus 0000:03 # 1MiB
iomem1: 20000000000-200001fffff : PCI Bus 0000:03 # 2MiB
iomem2: 20000000000-200002fffff : PCI Bus 0000:03 # 3MiB
iomem3: 20000000000-200003fffff : PCI Bus 0000:03 # 4MiB
iomem4: 20000000000-200004fffff : PCI Bus 0000:03 # 5MiB
Solve the double counting by moving old_size check later in
calculate_memsize() so that children_add_size is already accounted for.
After the patch, the bridge window retains its size as expected:
iomem0: 23fffd00000-23fffdfffff : PCI Bus 0000:03 # 1MiB
iomem1: 20000000000-200000fffff : PCI Bus 0000:03 # 1MiB
iomem2: 20000000000-200000fffff : PCI Bus 0000:03 # 1MiB
Fixes: a4ac9fea016f ("PCI : Calculate right add_size")
Link: https://lore.kernel.org/r/20240507102523.57320-2-ilpo.jarvinen@linux.intel.com
Tested-by: Lidong Wang <lidong.wang@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
