[PATCH v7 2/4] topology: use bin_attribute to break the size limitation of cpumap ABI

Barry Song
2021-07-15T11:59:48Z

From: Tian Tao <tiantao6@hisilicon.com>

Reading /sys/devices/system/cpu/cpuX/topology/ returns cpu topology.
However, the size of this file is limited to PAGE_SIZE because of
the limitation for sysfs attribute.
This patch moves to use bin_attribute to extend the ABI to be more
than one page so that cpumap bitmask and list won't be potentially
trimmed.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
---
drivers/base/topology.c | 115 ++++++++++++++++++++++------------------
1 file changed, 63 insertions(+), 52 deletions(-)

diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index 4d254fcc93d1..dd3980124e33 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -21,25 +21,27 @@ static ssize_t name##_show(struct device *dev, \
return sysfs_emit(buf, "%d\n", topology_##name(dev->id)); \
}

-#define define_siblings_show_map(name, mask) \
-static ssize_t name##_show(struct device *dev, \
- struct device_attribute *attr, char *buf) \
-{ \
- return cpumap_print_to_pagebuf(false, buf, topology_##mask(dev->id));\
+#define define_siblings_read_func(name, mask) \
+static ssize_t name##_read(struct file *file, struct kobject *kobj, \
+ struct bin_attribute *attr, char *buf, \
+ loff_t off, size_t count) \
+{ \
+ struct device *dev = kobj_to_dev(kobj); \
+ \
+ return cpumap_print_to_buf(false, buf, topology_##mask(dev->id), \
+ off, count); \
+} \
+ \
+static ssize_t name##_list_read(struct file *file, struct kobject *kobj, \
+ struct bin_attribute *attr, char *buf, \
+ loff_t off, size_t count) \
+{ \
+ struct device *dev = kobj_to_dev(kobj); \
+ \
+ return cpumap_print_to_buf(true, buf, topology_##mask(dev->id), \
+ off, count); \
}

-#define define_siblings_show_list(name, mask) \
-static ssize_t name##_list_show(struct device *dev, \
- struct device_attribute *attr, \
- char *buf) \
-{ \
- return cpumap_print_to_pagebuf(true, buf, topology_##mask(dev->id));\
-}
-
-#define define_siblings_show_func(name, mask) \
- define_siblings_show_map(name, mask); \
- define_siblings_show_list(name, mask)
-
define_id_show_func(physical_package_id);
static DEVICE_ATTR_RO(physical_package_id);

@@ -49,71 +51,80 @@ static DEVICE_ATTR_RO(die_id);
define_id_show_func(core_id);
static DEVICE_ATTR_RO(core_id);

-define_siblings_show_func(thread_siblings, sibling_cpumask);
-static DEVICE_ATTR_RO(thread_siblings);
-static DEVICE_ATTR_RO(thread_siblings_list);
+define_siblings_read_func(thread_siblings, sibling_cpumask);
+static BIN_ATTR_RO(thread_siblings, 0);
+static BIN_ATTR_RO(thread_siblings_list, 0);

-define_siblings_show_func(core_cpus, sibling_cpumask);
-static DEVICE_ATTR_RO(core_cpus);
-static DEVICE_ATTR_RO(core_cpus_list);
+define_siblings_read_func(core_cpus, sibling_cpumask);
+static BIN_ATTR_RO(core_cpus, 0);
+static BIN_ATTR_RO(core_cpus_list, 0);

-define_siblings_show_func(core_siblings, core_cpumask);
-static DEVICE_ATTR_RO(core_siblings);
-static DEVICE_ATTR_RO(core_siblings_list);
+define_siblings_read_func(core_siblings, core_cpumask);
+static BIN_ATTR_RO(core_siblings, 0);
+static BIN_ATTR_RO(core_siblings_list, 0);

-define_siblings_show_func(die_cpus, die_cpumask);
-static DEVICE_ATTR_RO(die_cpus);
-static DEVICE_ATTR_RO(die_cpus_list);
+define_siblings_read_func(die_cpus, die_cpumask);
+static BIN_ATTR_RO(die_cpus, 0);
+static BIN_ATTR_RO(die_cpus_list, 0);

-define_siblings_show_func(package_cpus, core_cpumask);
-static DEVICE_ATTR_RO(package_cpus);
-static DEVICE_ATTR_RO(package_cpus_list);
+define_siblings_read_func(package_cpus, core_cpumask);
+static BIN_ATTR_RO(package_cpus, 0);
+static BIN_ATTR_RO(package_cpus_list, 0);

#ifdef CONFIG_SCHED_BOOK
define_id_show_func(book_id);
static DEVICE_ATTR_RO(book_id);
-define_siblings_show_func(book_siblings, book_cpumask);
-static DEVICE_ATTR_RO(book_siblings);
-static DEVICE_ATTR_RO(book_siblings_list);
+define_siblings_read_func(book_siblings, book_cpumask);
+static BIN_ATTR_RO(book_siblings, 0);
+static BIN_ATTR_RO(book_siblings_list, 0);
#endif

#ifdef CONFIG_SCHED_DRAWER
define_id_show_func(drawer_id);
static DEVICE_ATTR_RO(drawer_id);
-define_siblings_show_func(drawer_siblings, drawer_cpumask);
-static DEVICE_ATTR_RO(drawer_siblings);
-static DEVICE_ATTR_RO(drawer_siblings_list);
+define_siblings_read_func(drawer_siblings, drawer_cpumask);
+static BIN_ATTR_RO(drawer_siblings, 0);
+static BIN_ATTR_RO(drawer_siblings_list, 0);
#endif

+static struct bin_attribute *bin_attrs[] = {
+ &bin_attr_core_cpus,
+ &bin_attr_core_cpus_list,
+ &bin_attr_thread_siblings,
+ &bin_attr_thread_siblings_list,
+ &bin_attr_core_siblings,
+ &bin_attr_core_siblings_list,
+ &bin_attr_die_cpus,
+ &bin_attr_die_cpus_list,
+ &bin_attr_package_cpus,
+ &bin_attr_package_cpus_list,
+#ifdef CONFIG_SCHED_BOOK
+ &bin_attr_book_siblings,
+ &bin_attr_book_siblings_list,
+#endif
+#ifdef CONFIG_SCHED_DRAWER
+ &bin_attr_drawer_siblings,
+ &bin_attr_drawer_siblings_list,
+#endif
+ NULL
+};
+
static struct attribute *default_attrs[] = {
&dev_attr_physical_package_id.attr,
&dev_attr_die_id.attr,
&dev_attr_core_id.attr,
- &dev_attr_thread_siblings.attr,
- &dev_attr_thread_siblings_list.attr,
- &dev_attr_core_cpus.attr,
- &dev_attr_core_cpus_list.attr,
- &dev_attr_core_siblings.attr,
- &dev_attr_core_siblings_list.attr,
- &dev_attr_die_cpus.attr,
- &dev_attr_die_cpus_list.attr,
- &dev_attr_package_cpus.attr,
- &dev_attr_package_cpus_list.attr,
#ifdef CONFIG_SCHED_BOOK
&dev_attr_book_id.attr,
- &dev_attr_book_siblings.attr,
- &dev_attr_book_siblings_list.attr,
#endif
#ifdef CONFIG_SCHED_DRAWER
&dev_attr_drawer_id.attr,
- &dev_attr_drawer_siblings.attr,
- &dev_attr_drawer_siblings_list.attr,
#endif
NULL
};

static const struct attribute_group topology_attr_group = {
.attrs = default_attrs,
+ .bin_attrs = bin_attrs,
.name = "topology"
};

--
2.25.1