[PATCH 17/20] alpha/PCI: Compute legacy size in pci_mmap_legacy_page_range()

Krzysztof Wilczyński
2026-04-10T07:15:39Z

Currently, pci_mmap_legacy_page_range() reads the legacy resource
size from bus->legacy_mem->size or bus->legacy_io->size. This
couples the mmap bounds check to the struct pci_bus fields that
will be removed when legacy attributes are converted to static
definitions.

Compute the size directly from the known constants (0x100000 for
memory, 0xffff for I/O) and shift by 5 bits for sparse systems.

Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
---
arch/alpha/kernel/pci-sysfs.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/alpha/kernel/pci-sysfs.c b/arch/alpha/kernel/pci-sysfs.c
index 27adfe6dbd5e..2da95d965e9c 100644
--- a/arch/alpha/kernel/pci-sysfs.c
+++ b/arch/alpha/kernel/pci-sysfs.c
@@ -180,8 +180,10 @@ int pci_mmap_legacy_page_range(struct pci_bus *bus, struct vm_area_struct *vma,
int sparse = has_sparse(hose, mmap_type);
unsigned long res_size;

- res_size = (mmap_type == pci_mmap_mem) ? bus->legacy_mem->size :
- bus->legacy_io->size;
+ res_size = (mmap_type == pci_mmap_mem) ? 0x100000 : 0xffff;
+ if (sparse)
+ res_size <<= 5;
+
if (!__legacy_mmap_fits(hose, vma, res_size, sparse))
return -EINVAL;

--
2.53.0