x86/intel_rdt: Add "info" files to resctrl file system
For the convenience of applications we make the decoded values of some of the CPUID values available in read-only (0444) files. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477692289-37412-5-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -26,6 +26,30 @@ extern struct list_head rdt_all_groups;
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int __init rdtgroup_init(void);
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/**
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* struct rftype - describe each file in the resctrl file system
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* @name: file name
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* @mode: access mode
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* @kf_ops: operations
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* @seq_show: show content of the file
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* @write: write to the file
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*/
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struct rftype {
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char *name;
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umode_t mode;
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struct kernfs_ops *kf_ops;
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int (*seq_show)(struct kernfs_open_file *of,
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struct seq_file *sf, void *v);
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/*
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* write() is the generic write callback which maps directly to
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* kernfs write operation and overrides all other operations.
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* Maximum write size is determined by ->max_write_len.
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*/
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ssize_t (*write)(struct kernfs_open_file *of,
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char *buf, size_t nbytes, loff_t off);
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};
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/**
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* struct rdt_resource - attributes of an RDT resource
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* @enabled: Is this feature enabled on this machine
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@ -23,6 +23,8 @@
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#include <linux/fs.h>
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#include <linux/sysfs.h>
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#include <linux/kernfs.h>
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#include <linux/seq_file.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <uapi/linux/magic.h>
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@ -34,6 +36,176 @@ struct kernfs_root *rdt_root;
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struct rdtgroup rdtgroup_default;
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LIST_HEAD(rdt_all_groups);
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/* Kernel fs node for "info" directory under root */
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static struct kernfs_node *kn_info;
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/* set uid and gid of rdtgroup dirs and files to that of the creator */
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static int rdtgroup_kn_set_ugid(struct kernfs_node *kn)
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{
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struct iattr iattr = { .ia_valid = ATTR_UID | ATTR_GID,
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.ia_uid = current_fsuid(),
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.ia_gid = current_fsgid(), };
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if (uid_eq(iattr.ia_uid, GLOBAL_ROOT_UID) &&
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gid_eq(iattr.ia_gid, GLOBAL_ROOT_GID))
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return 0;
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return kernfs_setattr(kn, &iattr);
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}
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static int rdtgroup_add_file(struct kernfs_node *parent_kn, struct rftype *rft)
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{
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struct kernfs_node *kn;
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int ret;
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kn = __kernfs_create_file(parent_kn, rft->name, rft->mode,
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0, rft->kf_ops, rft, NULL, NULL);
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if (IS_ERR(kn))
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return PTR_ERR(kn);
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ret = rdtgroup_kn_set_ugid(kn);
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if (ret) {
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kernfs_remove(kn);
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return ret;
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}
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return 0;
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}
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static int rdtgroup_add_files(struct kernfs_node *kn, struct rftype *rfts,
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int len)
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{
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struct rftype *rft;
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int ret;
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lockdep_assert_held(&rdtgroup_mutex);
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for (rft = rfts; rft < rfts + len; rft++) {
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ret = rdtgroup_add_file(kn, rft);
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if (ret)
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goto error;
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}
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return 0;
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error:
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pr_warn("Failed to add %s, err=%d\n", rft->name, ret);
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while (--rft >= rfts)
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kernfs_remove_by_name(kn, rft->name);
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return ret;
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}
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static int rdtgroup_seqfile_show(struct seq_file *m, void *arg)
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{
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struct kernfs_open_file *of = m->private;
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struct rftype *rft = of->kn->priv;
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if (rft->seq_show)
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return rft->seq_show(of, m, arg);
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return 0;
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}
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static ssize_t rdtgroup_file_write(struct kernfs_open_file *of, char *buf,
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size_t nbytes, loff_t off)
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{
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struct rftype *rft = of->kn->priv;
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if (rft->write)
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return rft->write(of, buf, nbytes, off);
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return -EINVAL;
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}
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static struct kernfs_ops rdtgroup_kf_single_ops = {
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.atomic_write_len = PAGE_SIZE,
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.write = rdtgroup_file_write,
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.seq_show = rdtgroup_seqfile_show,
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};
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static int rdt_num_closids_show(struct kernfs_open_file *of,
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struct seq_file *seq, void *v)
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{
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struct rdt_resource *r = of->kn->parent->priv;
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seq_printf(seq, "%d\n", r->num_closid);
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return 0;
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}
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static int rdt_cbm_mask_show(struct kernfs_open_file *of,
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struct seq_file *seq, void *v)
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{
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struct rdt_resource *r = of->kn->parent->priv;
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seq_printf(seq, "%x\n", r->max_cbm);
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return 0;
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}
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/* rdtgroup information files for one cache resource. */
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static struct rftype res_info_files[] = {
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{
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.name = "num_closids",
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.mode = 0444,
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.kf_ops = &rdtgroup_kf_single_ops,
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.seq_show = rdt_num_closids_show,
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},
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{
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.name = "cbm_mask",
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.mode = 0444,
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.kf_ops = &rdtgroup_kf_single_ops,
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.seq_show = rdt_cbm_mask_show,
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},
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};
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static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
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{
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struct kernfs_node *kn_subdir;
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struct rdt_resource *r;
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int ret;
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/* create the directory */
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kn_info = kernfs_create_dir(parent_kn, "info", parent_kn->mode, NULL);
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if (IS_ERR(kn_info))
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return PTR_ERR(kn_info);
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kernfs_get(kn_info);
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for_each_enabled_rdt_resource(r) {
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kn_subdir = kernfs_create_dir(kn_info, r->name,
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kn_info->mode, r);
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if (IS_ERR(kn_subdir)) {
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ret = PTR_ERR(kn_subdir);
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goto out_destroy;
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}
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kernfs_get(kn_subdir);
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ret = rdtgroup_kn_set_ugid(kn_subdir);
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if (ret)
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goto out_destroy;
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ret = rdtgroup_add_files(kn_subdir, res_info_files,
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ARRAY_SIZE(res_info_files));
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if (ret)
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goto out_destroy;
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kernfs_activate(kn_subdir);
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}
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/*
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* This extra ref will be put in kernfs_remove() and guarantees
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* that @rdtgrp->kn is always accessible.
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*/
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kernfs_get(kn_info);
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ret = rdtgroup_kn_set_ugid(kn_info);
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if (ret)
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goto out_destroy;
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kernfs_activate(kn_info);
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return 0;
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out_destroy:
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kernfs_remove(kn_info);
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return ret;
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}
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static void l3_qos_cfg_update(void *arg)
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{
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bool *enable = arg;
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@ -137,6 +309,10 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
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goto out_cdp;
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}
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ret = rdtgroup_create_info_dir(rdtgroup_default.kn);
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if (ret)
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goto out_cdp;
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dentry = kernfs_mount(fs_type, flags, rdt_root,
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RDTGROUP_SUPER_MAGIC, NULL);
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if (IS_ERR(dentry))
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@ -191,6 +367,14 @@ static int reset_all_cbms(struct rdt_resource *r)
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return 0;
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}
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/*
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* Forcibly remove all of subdirectories under root.
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*/
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static void rmdir_all_sub(void)
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{
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kernfs_remove(kn_info);
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}
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static void rdt_kill_sb(struct super_block *sb)
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{
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struct rdt_resource *r;
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@ -201,6 +385,7 @@ static void rdt_kill_sb(struct super_block *sb)
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for_each_enabled_rdt_resource(r)
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reset_all_cbms(r);
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cdp_disable();
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rmdir_all_sub();
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static_branch_disable(&rdt_enable_key);
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kernfs_kill_sb(sb);
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mutex_unlock(&rdtgroup_mutex);
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