[PATCH v4 12/24] alpha/PCI: Use BAR index in sysfs attr->private instead of resource pointer

Krzysztof Wilczyński
2026-04-11T08:02:35Z

Currently, Alpha's pci_create_one_attr() stores a resource pointer in
attr->private, and pci_mmap_resource() loops through all BARs to find
the matching index.

Thus, store the BAR index directly in attr->private and retrieve the
resource via pci_resource_n(). This eliminates the loop and aligns
with the convention used by the generic PCI sysfs code.

While at it, add parentheses around the bitwise flag test in
pci_mmap_resource() to make the precedence explicit, and to
match the preferred style.

The PCI core change was first added in the commit dca40b186b75 ("PCI:
Use BAR index in sysfs attr->private instead of resource pointer").

Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
---
arch/alpha/kernel/pci-sysfs.c | 17 ++++++-----------
1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/arch/alpha/kernel/pci-sysfs.c b/arch/alpha/kernel/pci-sysfs.c
index 2324720c3e83..c84867ce31f5 100644
--- a/arch/alpha/kernel/pci-sysfs.c
+++ b/arch/alpha/kernel/pci-sysfs.c
@@ -69,25 +69,20 @@ static int pci_mmap_resource(struct kobject *kobj,
struct vm_area_struct *vma, int sparse)
{
struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
- struct resource *res = attr->private;
+ int barno = (unsigned long)attr->private;
+ struct resource *res = pci_resource_n(pdev, barno);
enum pci_mmap_state mmap_type;
struct pci_bus_region bar;
- int i, ret;
+ int ret;

ret = security_locked_down(LOCKDOWN_PCI_ACCESS);
if (ret)
return ret;

- for (i = 0; i < PCI_STD_NUM_BARS; i++)
- if (res == &pdev->resource[i])
- break;
- if (i >= PCI_STD_NUM_BARS)
- return -ENODEV;
-
- if (res->flags & IORESOURCE_MEM && iomem_is_exclusive(res->start))
+ if ((res->flags & IORESOURCE_MEM) && iomem_is_exclusive(res->start))
return -EINVAL;

- if (!__pci_mmap_fits(pdev, i, vma, sparse))
+ if (!__pci_mmap_fits(pdev, barno, vma, sparse))
return -EINVAL;

pcibios_resource_to_bus(pdev->bus, &bar, res);
@@ -170,7 +165,7 @@ static int pci_create_one_attr(struct pci_dev *pdev, int num, char *name,
res_attr->attr.name = name;
res_attr->attr.mode = S_IRUSR | S_IWUSR;
res_attr->size = sparse ? size << 5 : size;
- res_attr->private = &pdev->resource[num];
+ res_attr->private = (void *)(unsigned long)num;
return sysfs_create_bin_file(&pdev->dev.kobj, res_attr);
}

--
2.53.0