[PATCH v6 17/24] alpha/PCI: Convert resource files to static attributes

Krzysztof Wilczyński
2026-04-22T16:16:37Z

Currently, Alpha's PCI resource files (resourceN, resourceN_sparse,
resourceN_dense) are dynamically created by pci_create_resource_files(),
which overrides the generic __weak implementation. The current code
allocates bin_attributes at runtime and manages them via the res_attr[]
and res_attr_wc[] fields in struct pci_dev.

Thus, convert to static const attributes with three attribute groups
(plain, sparse, dense), each with an .is_bin_visible callback that
checks resource length, has_sparse(), and sparse_mem_mmap_fits(). A
.bin_size callback provides the resource size to the kernfs node, with
the sparse variant shifting by 5 bits for byte-level addressing.

Register the groups via ARCH_PCI_DEV_GROUPS so the driver model handles
creation and removal automatically.

Use the new pci_resource_is_mem() helper for the type check, replacing
the open-coded bitwise flag test.

Finally, remove pci_create_resource_files(), pci_remove_resource_files(),
pci_create_attr(), and pci_create_one_attr() which are no longer needed.

Tested-by: Magnus Lindholm <linmag7@gmail.com>
Acked-by: Magnus Lindholm <linmag7@gmail.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
---
arch/alpha/include/asm/pci.h | 9 ++
arch/alpha/kernel/pci-sysfs.c | 291 +++++++++++++++++++---------------
2 files changed, 172 insertions(+), 128 deletions(-)

diff --git a/arch/alpha/include/asm/pci.h b/arch/alpha/include/asm/pci.h
index 6c04fcbdc8ed..ef19295f2e33 100644
--- a/arch/alpha/include/asm/pci.h
+++ b/arch/alpha/include/asm/pci.h
@@ -88,4 +88,13 @@ extern void pci_adjust_legacy_attr(struct pci_bus *bus,
enum pci_mmap_state mmap_type);
#define HAVE_PCI_LEGACY 1

+extern const struct attribute_group pci_dev_resource_attr_group;
+extern const struct attribute_group pci_dev_resource_sparse_attr_group;
+extern const struct attribute_group pci_dev_resource_dense_attr_group;
+
+#define ARCH_PCI_DEV_GROUPS \
+ &pci_dev_resource_attr_group, \
+ &pci_dev_resource_sparse_attr_group, \
+ &pci_dev_resource_dense_attr_group,
+
#endif /* __ALPHA_PCI_H */
diff --git a/arch/alpha/kernel/pci-sysfs.c b/arch/alpha/kernel/pci-sysfs.c
index 3108c165b3d8..2e9693e5abe1 100644
--- a/arch/alpha/kernel/pci-sysfs.c
+++ b/arch/alpha/kernel/pci-sysfs.c
@@ -12,8 +12,6 @@

#include <linux/sched.h>
#include <linux/security.h>
-#include <linux/stat.h>
-#include <linux/slab.h>
#include <linux/pci.h>

static int hose_mmap_page_range(struct pci_controller *hose,
@@ -124,34 +122,6 @@ pci_dev_resource##_bar##_suffix##_attr = { \
__pci_dev_resource_attr(_bar, resource##_bar##_dense, _dense, \
pci_mmap_resource_dense)

-/**
- * pci_remove_resource_files - cleanup resource files
- * @pdev: pci_dev to cleanup
- *
- * If we created resource files for @dev, remove them from sysfs and
- * free their resources.
- */
-void pci_remove_resource_files(struct pci_dev *pdev)
-{
- int i;
-
- for (i = 0; i < PCI_STD_NUM_BARS; i++) {
- struct bin_attribute *res_attr;
-
- res_attr = pdev->res_attr[i];
- if (res_attr) {
- sysfs_remove_bin_file(&pdev->dev.kobj, res_attr);
- kfree(res_attr);
- }
-
- res_attr = pdev->res_attr_wc[i];
- if (res_attr) {
- sysfs_remove_bin_file(&pdev->dev.kobj, res_attr);
- kfree(res_attr);
- }
- }
-}
-
static int sparse_mem_mmap_fits(struct pci_dev *pdev, int num)
{
struct pci_bus_region bar;
@@ -171,104 +141,6 @@ static int sparse_mem_mmap_fits(struct pci_dev *pdev, int num)
return bar.end < sparse_size;
}

-static int pci_create_one_attr(struct pci_dev *pdev, int num, char *name,
- char *suffix, struct bin_attribute *res_attr,
- unsigned long sparse)
-{
- size_t size = pci_resource_len(pdev, num);
-
- sprintf(name, "resource%d%s", num, suffix);
- res_attr->mmap = sparse ? pci_mmap_resource_sparse :
- pci_mmap_resource_dense;
- res_attr->attr.name = name;
- res_attr->attr.mode = S_IRUSR | S_IWUSR;
- res_attr->size = sparse ? size << 5 : size;
- res_attr->private = (void *)(unsigned long)num;
- return sysfs_create_bin_file(&pdev->dev.kobj, res_attr);
-}
-
-static int pci_create_attr(struct pci_dev *pdev, int num)
-{
- /* allocate attribute structure, piggyback attribute name */
- int retval, nlen1, nlen2 = 0, res_count = 1;
- unsigned long sparse_base, dense_base;
- struct bin_attribute *attr;
- struct pci_controller *hose = pdev->sysdata;
- char *suffix, *attr_name;
-
- suffix = ""; /* Assume bwx machine, normal resourceN files. */
- nlen1 = 10;
-
- if (pci_resource_is_mem(pdev, num)) {
- sparse_base = hose->sparse_mem_base;
- dense_base = hose->dense_mem_base;
- if (sparse_base && !sparse_mem_mmap_fits(pdev, num)) {
- sparse_base = 0;
- suffix = "_dense";
- nlen1 = 16; /* resourceN_dense */
- }
- } else {
- sparse_base = hose->sparse_io_base;
- dense_base = hose->dense_io_base;
- }
-
- if (sparse_base) {
- suffix = "_sparse";
- nlen1 = 17;
- if (dense_base) {
- nlen2 = 16; /* resourceN_dense */
- res_count = 2;
- }
- }
-
- attr = kzalloc(sizeof(*attr) * res_count + nlen1 + nlen2, GFP_ATOMIC);
- if (!attr)
- return -ENOMEM;
-
- /* Create bwx, sparse or single dense file */
- attr_name = (char *)(attr + res_count);
- pdev->res_attr[num] = attr;
- retval = pci_create_one_attr(pdev, num, attr_name, suffix, attr,
- sparse_base);
- if (retval || res_count == 1)
- return retval;
-
- /* Create dense file */
- attr_name += nlen1;
- attr++;
- pdev->res_attr_wc[num] = attr;
- return pci_create_one_attr(pdev, num, attr_name, "_dense", attr, 0);
-}
-
-/**
- * pci_create_resource_files - create resource files in sysfs for @pdev
- * @pdev: pci_dev in question
- *
- * Walk the resources in @dev creating files for each resource available.
- *
- * Return: %0 on success, or negative error code
- */
-int pci_create_resource_files(struct pci_dev *pdev)
-{
- int i;
- int retval;
-
- /* Expose the PCI resources from this device as files */
- for (i = 0; i < PCI_STD_NUM_BARS; i++) {
-
- /* skip empty resources */
- if (!pci_resource_len(pdev, i))
- continue;
-
- retval = pci_create_attr(pdev, i);
- if (retval) {
- pci_remove_resource_files(pdev);
- return retval;
- }
- }
- return 0;
-}
-
/* Legacy I/O bus mapping stuff. */

static int __legacy_mmap_fits(struct pci_controller *hose,
@@ -388,3 +260,166 @@ int pci_legacy_write(struct pci_bus *bus, loff_t port, u32 val, size_t size)
}
return -EINVAL;
}
+
+pci_dev_resource_attr(0);
+pci_dev_resource_attr(1);
+pci_dev_resource_attr(2);
+pci_dev_resource_attr(3);
+pci_dev_resource_attr(4);
+pci_dev_resource_attr(5);
+
+pci_dev_resource_sparse_attr(0);
+pci_dev_resource_sparse_attr(1);
+pci_dev_resource_sparse_attr(2);
+pci_dev_resource_sparse_attr(3);
+pci_dev_resource_sparse_attr(4);
+pci_dev_resource_sparse_attr(5);
+
+pci_dev_resource_dense_attr(0);
+pci_dev_resource_dense_attr(1);
+pci_dev_resource_dense_attr(2);
+pci_dev_resource_dense_attr(3);
+pci_dev_resource_dense_attr(4);
+pci_dev_resource_dense_attr(5);
+
+static inline enum pci_mmap_state pci_bar_mmap_type(struct pci_dev *pdev,
+ int bar)
+{
+ return pci_resource_is_mem(pdev, bar) ? pci_mmap_mem : pci_mmap_io;
+}
+
+static inline umode_t __pci_dev_resource_is_visible(struct kobject *kobj,
+ const struct bin_attribute *a,
+ int bar)
+{
+ struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+
+ if (!pci_resource_len(pdev, bar))
+ return 0;
+
+ return a->attr.mode;
+}
+
+static umode_t pci_dev_resource_is_visible(struct kobject *kobj,
+ const struct bin_attribute *a,
+ int bar)
+{
+ struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+ struct pci_controller *hose = pdev->sysdata;
+
+ if (has_sparse(hose, pci_bar_mmap_type(pdev, bar)))
+ return 0;
+
+ return __pci_dev_resource_is_visible(kobj, a, bar);
+}
+
+static umode_t pci_dev_resource_sparse_is_visible(struct kobject *kobj,
+ const struct bin_attribute *a,
+ int bar)
+{
+ struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+ struct pci_controller *hose = pdev->sysdata;
+ enum pci_mmap_state type = pci_bar_mmap_type(pdev, bar);
+
+ if (!has_sparse(hose, type))
+ return 0;
+
+ if (type == pci_mmap_mem && !sparse_mem_mmap_fits(pdev, bar))
+ return 0;
+
+ return __pci_dev_resource_is_visible(kobj, a, bar);
+}
+
+static umode_t pci_dev_resource_dense_is_visible(struct kobject *kobj,
+ const struct bin_attribute *a,
+ int bar)
+{
+ struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+ struct pci_controller *hose = pdev->sysdata;
+ enum pci_mmap_state type = pci_bar_mmap_type(pdev, bar);
+ unsigned long dense_base;
+
+ if (!has_sparse(hose, type))
+ return 0;
+
+ if (type == pci_mmap_mem && !sparse_mem_mmap_fits(pdev, bar))
+ return __pci_dev_resource_is_visible(kobj, a, bar);
+
+ dense_base = (type == pci_mmap_mem) ? hose->dense_mem_base :
+ hose->dense_io_base;
+ if (!dense_base)
+ return 0;
+
+ return __pci_dev_resource_is_visible(kobj, a, bar);
+}
+
+static inline size_t __pci_dev_resource_bin_size(struct kobject *kobj,
+ int bar, bool sparse)
+{
+ struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+ size_t size = pci_resource_len(pdev, bar);
+
+ return sparse ? size << 5 : size;
+}
+
+static size_t pci_dev_resource_bin_size(struct kobject *kobj,
+ const struct bin_attribute *a,
+ int bar)
+{
+ return __pci_dev_resource_bin_size(kobj, bar, false);
+}
+
+static size_t pci_dev_resource_sparse_bin_size(struct kobject *kobj,
+ const struct bin_attribute *a,
+ int bar)
+{
+ return __pci_dev_resource_bin_size(kobj, bar, true);
+}
+
+static const struct bin_attribute *const pci_dev_resource_attrs[] = {
+ &pci_dev_resource0_attr,
+ &pci_dev_resource1_attr,
+ &pci_dev_resource2_attr,
+ &pci_dev_resource3_attr,
+ &pci_dev_resource4_attr,
+ &pci_dev_resource5_attr,
+ NULL,
+};
+
+static const struct bin_attribute *const pci_dev_resource_sparse_attrs[] = {
+ &pci_dev_resource0_sparse_attr,
+ &pci_dev_resource1_sparse_attr,
+ &pci_dev_resource2_sparse_attr,
+ &pci_dev_resource3_sparse_attr,
+ &pci_dev_resource4_sparse_attr,
+ &pci_dev_resource5_sparse_attr,
+ NULL,
+};
+
+static const struct bin_attribute *const pci_dev_resource_dense_attrs[] = {
+ &pci_dev_resource0_dense_attr,
+ &pci_dev_resource1_dense_attr,
+ &pci_dev_resource2_dense_attr,
+ &pci_dev_resource3_dense_attr,
+ &pci_dev_resource4_dense_attr,
+ &pci_dev_resource5_dense_attr,
+ NULL,
+};
+
+const struct attribute_group pci_dev_resource_attr_group = {
+ .bin_attrs = pci_dev_resource_attrs,
+ .is_bin_visible = pci_dev_resource_is_visible,
+ .bin_size = pci_dev_resource_bin_size,
+};
+
+const struct attribute_group pci_dev_resource_sparse_attr_group = {
+ .bin_attrs = pci_dev_resource_sparse_attrs,
+ .is_bin_visible = pci_dev_resource_sparse_is_visible,
+ .bin_size = pci_dev_resource_sparse_bin_size,
+};
+
+const struct attribute_group pci_dev_resource_dense_attr_group = {
+ .bin_attrs = pci_dev_resource_dense_attrs,
+ .is_bin_visible = pci_dev_resource_dense_is_visible,
+ .bin_size = pci_dev_resource_bin_size,
+};
--
2.54.0