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![Phil Auld](/assets/img/avatar_default.png)
Using bin_attributes with a 0 size causes fstat and friends to return that 0 size. This breaks userspace code that retrieves the size before reading the file. Rather than reverting75bd50fa84
("drivers/base/node.c: use bin_attribute to break the size limitation of cpumap ABI") let's put in a size value at compile time. For cpulist the maximum size is on the order of NR_CPUS * (ceil(log10(NR_CPUS)) + 1)/2 which for 8192 is 20480 (8192 * 5)/2. In order to get near that you'd need a system with every other CPU on one node. For example: (0,2,4,8, ... ). To simplify the math and support larger NR_CPUS in the future we are using (NR_CPUS * 7)/2. We also set it to a min of PAGE_SIZE to retain the older behavior for smaller NR_CPUS. The cpumap file the size works out to be NR_CPUS/4 + NR_CPUS/32 - 1 (or NR_CPUS * 9/32 - 1) including the ","s. Add a set of macros for these values to cpumask.h so they can be used in multiple places. Apply these to the handful of such files in drivers/base/topology.c as well as node.c. As an example, on an 80 cpu 4-node system (NR_CPUS == 8192): before: -r--r--r--. 1 root root 0 Jul 12 14:08 system/node/node0/cpulist -r--r--r--. 1 root root 0 Jul 11 17:25 system/node/node0/cpumap after: -r--r--r--. 1 root root 28672 Jul 13 11:32 system/node/node0/cpulist -r--r--r--. 1 root root 4096 Jul 13 11:31 system/node/node0/cpumap CONFIG_NR_CPUS = 16384 -r--r--r--. 1 root root 57344 Jul 13 14:03 system/node/node0/cpulist -r--r--r--. 1 root root 4607 Jul 13 14:02 system/node/node0/cpumap The actual number of cpus doesn't matter for the reported size since they are based on NR_CPUS. Fixes:75bd50fa84
("drivers/base/node.c: use bin_attribute to break the size limitation of cpumap ABI") Fixes:bb9ec13d15
("topology: use bin_attribute to break the size limitation of cpumap ABI") Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Yury Norov <yury.norov@gmail.com> Cc: stable@vger.kernel.org Acked-by: Yury Norov <yury.norov@gmail.com> (for include/linux/cpumask.h) Signed-off-by: Phil Auld <pauld@redhat.com> Link: https://lore.kernel.org/r/20220715134924.3466194-1-pauld@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
194 lines
5.4 KiB
C
194 lines
5.4 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* driver/base/topology.c - Populate sysfs with cpu topology information
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*
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* Written by: Zhang Yanmin, Intel Corporation
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*
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* Copyright (C) 2006, Intel Corp.
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*
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* All rights reserved.
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*/
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#include <linux/mm.h>
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#include <linux/cpu.h>
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#include <linux/module.h>
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#include <linux/hardirq.h>
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#include <linux/topology.h>
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#define define_id_show_func(name, fmt) \
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static ssize_t name##_show(struct device *dev, \
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struct device_attribute *attr, char *buf) \
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{ \
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return sysfs_emit(buf, fmt "\n", topology_##name(dev->id)); \
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}
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#define define_siblings_read_func(name, mask) \
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static ssize_t name##_read(struct file *file, struct kobject *kobj, \
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struct bin_attribute *attr, char *buf, \
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loff_t off, size_t count) \
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{ \
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struct device *dev = kobj_to_dev(kobj); \
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\
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return cpumap_print_bitmask_to_buf(buf, topology_##mask(dev->id), \
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off, count); \
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} \
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\
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static ssize_t name##_list_read(struct file *file, struct kobject *kobj, \
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struct bin_attribute *attr, char *buf, \
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loff_t off, size_t count) \
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{ \
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struct device *dev = kobj_to_dev(kobj); \
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\
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return cpumap_print_list_to_buf(buf, topology_##mask(dev->id), \
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off, count); \
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}
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define_id_show_func(physical_package_id, "%d");
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static DEVICE_ATTR_RO(physical_package_id);
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#ifdef TOPOLOGY_DIE_SYSFS
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define_id_show_func(die_id, "%d");
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static DEVICE_ATTR_RO(die_id);
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#endif
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#ifdef TOPOLOGY_CLUSTER_SYSFS
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define_id_show_func(cluster_id, "%d");
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static DEVICE_ATTR_RO(cluster_id);
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#endif
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define_id_show_func(core_id, "%d");
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static DEVICE_ATTR_RO(core_id);
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define_id_show_func(ppin, "0x%llx");
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static DEVICE_ATTR_ADMIN_RO(ppin);
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define_siblings_read_func(thread_siblings, sibling_cpumask);
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static BIN_ATTR_RO(thread_siblings, CPUMAP_FILE_MAX_BYTES);
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static BIN_ATTR_RO(thread_siblings_list, CPULIST_FILE_MAX_BYTES);
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define_siblings_read_func(core_cpus, sibling_cpumask);
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static BIN_ATTR_RO(core_cpus, CPUMAP_FILE_MAX_BYTES);
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static BIN_ATTR_RO(core_cpus_list, CPULIST_FILE_MAX_BYTES);
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define_siblings_read_func(core_siblings, core_cpumask);
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static BIN_ATTR_RO(core_siblings, CPUMAP_FILE_MAX_BYTES);
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static BIN_ATTR_RO(core_siblings_list, CPULIST_FILE_MAX_BYTES);
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#ifdef TOPOLOGY_CLUSTER_SYSFS
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define_siblings_read_func(cluster_cpus, cluster_cpumask);
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static BIN_ATTR_RO(cluster_cpus, CPUMAP_FILE_MAX_BYTES);
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static BIN_ATTR_RO(cluster_cpus_list, CPULIST_FILE_MAX_BYTES);
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#endif
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#ifdef TOPOLOGY_DIE_SYSFS
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define_siblings_read_func(die_cpus, die_cpumask);
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static BIN_ATTR_RO(die_cpus, CPUMAP_FILE_MAX_BYTES);
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static BIN_ATTR_RO(die_cpus_list, CPULIST_FILE_MAX_BYTES);
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#endif
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define_siblings_read_func(package_cpus, core_cpumask);
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static BIN_ATTR_RO(package_cpus, CPUMAP_FILE_MAX_BYTES);
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static BIN_ATTR_RO(package_cpus_list, CPULIST_FILE_MAX_BYTES);
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#ifdef TOPOLOGY_BOOK_SYSFS
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define_id_show_func(book_id, "%d");
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static DEVICE_ATTR_RO(book_id);
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define_siblings_read_func(book_siblings, book_cpumask);
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static BIN_ATTR_RO(book_siblings, CPUMAP_FILE_MAX_BYTES);
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static BIN_ATTR_RO(book_siblings_list, CPULIST_FILE_MAX_BYTES);
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#endif
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#ifdef TOPOLOGY_DRAWER_SYSFS
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define_id_show_func(drawer_id, "%d");
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static DEVICE_ATTR_RO(drawer_id);
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define_siblings_read_func(drawer_siblings, drawer_cpumask);
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static BIN_ATTR_RO(drawer_siblings, CPUMAP_FILE_MAX_BYTES);
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static BIN_ATTR_RO(drawer_siblings_list, CPULIST_FILE_MAX_BYTES);
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#endif
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static struct bin_attribute *bin_attrs[] = {
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&bin_attr_core_cpus,
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&bin_attr_core_cpus_list,
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&bin_attr_thread_siblings,
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&bin_attr_thread_siblings_list,
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&bin_attr_core_siblings,
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&bin_attr_core_siblings_list,
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#ifdef TOPOLOGY_CLUSTER_SYSFS
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&bin_attr_cluster_cpus,
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&bin_attr_cluster_cpus_list,
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#endif
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#ifdef TOPOLOGY_DIE_SYSFS
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&bin_attr_die_cpus,
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&bin_attr_die_cpus_list,
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#endif
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&bin_attr_package_cpus,
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&bin_attr_package_cpus_list,
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#ifdef TOPOLOGY_BOOK_SYSFS
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&bin_attr_book_siblings,
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&bin_attr_book_siblings_list,
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#endif
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#ifdef TOPOLOGY_DRAWER_SYSFS
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&bin_attr_drawer_siblings,
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&bin_attr_drawer_siblings_list,
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#endif
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NULL
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};
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static struct attribute *default_attrs[] = {
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&dev_attr_physical_package_id.attr,
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#ifdef TOPOLOGY_DIE_SYSFS
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&dev_attr_die_id.attr,
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#endif
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#ifdef TOPOLOGY_CLUSTER_SYSFS
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&dev_attr_cluster_id.attr,
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#endif
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&dev_attr_core_id.attr,
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#ifdef TOPOLOGY_BOOK_SYSFS
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&dev_attr_book_id.attr,
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#endif
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#ifdef TOPOLOGY_DRAWER_SYSFS
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&dev_attr_drawer_id.attr,
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#endif
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&dev_attr_ppin.attr,
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NULL
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};
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static umode_t topology_is_visible(struct kobject *kobj,
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struct attribute *attr, int unused)
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{
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if (attr == &dev_attr_ppin.attr && !topology_ppin(kobj_to_dev(kobj)->id))
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return 0;
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return attr->mode;
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}
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static const struct attribute_group topology_attr_group = {
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.attrs = default_attrs,
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.bin_attrs = bin_attrs,
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.is_visible = topology_is_visible,
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.name = "topology"
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};
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/* Add/Remove cpu_topology interface for CPU device */
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static int topology_add_dev(unsigned int cpu)
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{
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struct device *dev = get_cpu_device(cpu);
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return sysfs_create_group(&dev->kobj, &topology_attr_group);
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}
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static int topology_remove_dev(unsigned int cpu)
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{
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struct device *dev = get_cpu_device(cpu);
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sysfs_remove_group(&dev->kobj, &topology_attr_group);
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return 0;
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}
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static int __init topology_sysfs_init(void)
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{
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return cpuhp_setup_state(CPUHP_TOPOLOGY_PREPARE,
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"base/topology:prepare", topology_add_dev,
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topology_remove_dev);
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}
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device_initcall(topology_sysfs_init);
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