-----Original Message----- From: tiantao (H) Sent: Wednesday, May 26, 2021 7:26 PM To: Song Bao Hua (Barry Song) song.bao.hua@hisilicon.com; Jonathan Cameron jonathan.cameron@huawei.com Cc: linuxarm@openeuler.org; tiantao (H) tiantao6@hisilicon.com Subject: [PATCH v6] topology: use bin_attribute to avoid buff overflow
Reading sys/devices/system/cpu/cpu0/topology/ returns cpu topology. However, the size of this file is limited to PAGE_SIZE because of the limitation for sysfs attribute. so we use bin_attribute instead of attribute to avoid NR_CPUS too big to cause buff overflow.
This patch is based on the following discussion. https://www.spinics.net/lists/linux-doc/msg95921.html
Signed-off-by: Tian Tao tiantao6@hisilicon.com
v2: rewrite the function name##_read v3: remove the temp buffer. v4: rewrite the function name##_read v5: rewrite the patch v6: update the commit message
drivers/base/topology.c | 135
drivers/base/node.c also needs this change.
+++++++++++++++++++++++++++++------------------- 1 file changed, 83 insertions(+), 52 deletions(-)
diff --git a/drivers/base/topology.c b/drivers/base/topology.c index 4d254fc..c46b217 100644 --- a/drivers/base/topology.c +++ b/drivers/base/topology.c @@ -14,6 +14,9 @@ #include <linux/hardirq.h> #include <linux/topology.h>
+/* BUFF_SIZE need 9 chars per 32 bits. */ +#define BUFF_SIZE ((NR_CPUS/32)*9)
this is only true for bitmap, but not true for list.
#define define_id_show_func(name) \ static ssize_t name##_show(struct device *dev, \ struct device_attribute *attr, char *buf) \ @@ -21,25 +24,41 @@ 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); \
- int len; \
- void *data; \
- data = kvmalloc(BUFF_SIZE, GFP_KERNEL); \
- if (!data) \
return -ENOMEM; \- len = scnprintf(data, BUFF_SIZE, "%*pb\n", nr_cpu_ids, \
cpumask_bits(topology_##mask(dev->id))); \- len = memory_read_from_buffer(buf, count, &off, data, len); \
- kvfree(data); \
- return len; \
+} \
\+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); \
- int len; \
- void *data; \
- data = kvmalloc(BUFF_SIZE, GFP_KERNEL); \
- if (!data) \
return -ENOMEM; \- len = scnprintf(data, BUFF_SIZE, "%*pbl\n", nr_cpu_ids, \
cpumask_bits(topology_##mask(dev->id))); \
List could be more than BUFF_SIZE. In the worst case, For example, a system has 4096 cpus, the list could be:
0,1,3,5,7,9,---------4095 2,4,6,8,10,12.........4094
In most case, it could be simply like: 0-99, 100-199....
- len = memory_read_from_buffer(buf, count, &off, data, len); \
- kvfree(data); \
- return len; \
}
-#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 +68,83 @@ 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_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_cpus, sibling_cpumask); -static DEVICE_ATTR_RO(core_cpus); -static DEVICE_ATTR_RO(core_cpus_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(core_siblings, core_cpumask); -static DEVICE_ATTR_RO(core_siblings); -static DEVICE_ATTR_RO(core_siblings_list);
-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_read_func(package_cpus, core_cpumask); +static BIN_ATTR_RO(package_cpus, 0); +static BIN_ATTR_RO(package_cpus_list, 0);
-define_siblings_show_func(package_cpus, core_cpumask); -static DEVICE_ATTR_RO(package_cpus); -static DEVICE_ATTR_RO(package_cpus_list);
#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"
};
-- 2.7.4
Thanks Barry