mm/page_idle: constify 'struct bin_attribute'

The sysfs core now allows instances of 'struct bin_attribute' to be moved
into read-only memory.  Make use of that to protect them against
accidental or malicious modifications.

Link: https://lkml.kernel.org/r/20241216-sysfs-const-bin_attr-page_idle-v1-1-cc01ecc55196@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_idle.c b/mm/page_idle.c
index 41ea77f22011ebc88cd0fe1e40abad6d11ff9b08..947c7c7a37289ad386f140047f733d4388833546 100644 (file)
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -112,7 +112,7 @@ static void page_idle_clear_pte_refs(struct folio *folio)
 }
 
 static ssize_t page_idle_bitmap_read(struct file *file, struct kobject *kobj,
-                                    struct bin_attribute *attr, char *buf,
+                                    const struct bin_attribute *attr, char *buf,
                                     loff_t pos, size_t count)
 {
        u64 *out = (u64 *)buf;
@@ -157,7 +157,7 @@ static ssize_t page_idle_bitmap_read(struct file *file, struct kobject *kobj,
 }
 
 static ssize_t page_idle_bitmap_write(struct file *file, struct kobject *kobj,
-                                     struct bin_attribute *attr, char *buf,
+                                     const struct bin_attribute *attr, char *buf,
                                      loff_t pos, size_t count)
 {
        const u64 *in = (u64 *)buf;
@@ -193,17 +193,17 @@ static ssize_t page_idle_bitmap_write(struct file *file, struct kobject *kobj,
        return (char *)in - buf;
 }
 
-static struct bin_attribute page_idle_bitmap_attr =
+static const struct bin_attribute page_idle_bitmap_attr =
                __BIN_ATTR(bitmap, 0600,
                           page_idle_bitmap_read, page_idle_bitmap_write, 0);
 
-static struct bin_attribute *page_idle_bin_attrs[] = {
+static const struct bin_attribute *const page_idle_bin_attrs[] = {
        &page_idle_bitmap_attr,
        NULL,
 };
 
 static const struct attribute_group page_idle_attr_group = {
-       .bin_attrs = page_idle_bin_attrs,
+       .bin_attrs_new = page_idle_bin_attrs,
        .name = "page_idle",
 };