5.15-stable review patch. If anyone has any objections, please let me know.
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From: Ilpo Järvinen ilpo.jarvinen@linux.intel.com
[ 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.c... 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 --- drivers/pci/setup-bus.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 16d291e10627b..a159bfdfa2512 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -824,11 +824,9 @@ static resource_size_t calculate_memsize(resource_size_t size, size = min_size; if (old_size == 1) old_size = 0; - if (size < old_size) - size = old_size;
- size = ALIGN(max(size, add_size) + children_add_size, align); - return size; + size = max(size, add_size) + children_add_size; + return ALIGN(max(size, old_size), align); }
resource_size_t __weak pcibios_window_alignment(struct pci_bus *bus,