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authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-02 21:50:47 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-02 21:50:47 +0400
commitc0e8a139a5bb8add02b4111e9e1957d810d7285e (patch)
treef5f0695c7553c0f651ea3c714191dedf76e06c78 /kernel
parent033d9959ed2dc1029217d4165f80a71702dc578e (diff)
parenta6f00298b2ceaf50b4ab00e6ee3eb0206ac72fac (diff)
downloadlinux-c0e8a139a5bb8add02b4111e9e1957d810d7285e.tar.xz
Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo: - xattr support added. The implementation is shared with tmpfs. The usage is restricted and intended to be used to manage per-cgroup metadata by system software. tmpfs changes are routed through this branch with Hugh's permission. - cgroup subsystem ID handling simplified. * 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Define CGROUP_SUBSYS_COUNT according the configuration cgroup: Assign subsystem IDs during compile time cgroup: Do not depend on a given order when populating the subsys array cgroup: Wrap subsystem selection macro cgroup: Remove CGROUP_BUILTIN_SUBSYS_COUNT cgroup: net_prio: Do not define task_netpioidx() when not selected cgroup: net_cls: Do not define task_cls_classid() when not selected cgroup: net_cls: Move sock_update_classid() declaration to cls_cgroup.h cgroup: trivial fixes for Documentation/cgroups/cgroups.txt xattr: mark variable as uninitialized to make both gcc and smatch happy fs: add missing documentation to simple_xattr functions cgroup: add documentation on extended attributes usage cgroup: rename subsys_bits to subsys_mask cgroup: add xattr support cgroup: revise how we re-populate root directory xattr: extract simple_xattr code from tmpfs
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cgroup.c320
1 files changed, 219 insertions, 101 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 79818507e444..485cc1487ea2 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -88,11 +88,12 @@ static DEFINE_MUTEX(cgroup_root_mutex);
/*
* Generate an array of cgroup subsystem pointers. At boot time, this is
- * populated up to CGROUP_BUILTIN_SUBSYS_COUNT, and modular subsystems are
+ * populated with the built in subsystems, and modular subsystems are
* registered after that. The mutable section of this array is protected by
* cgroup_mutex.
*/
-#define SUBSYS(_x) &_x ## _subsys,
+#define SUBSYS(_x) [_x ## _subsys_id] = &_x ## _subsys,
+#define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option)
static struct cgroup_subsys *subsys[CGROUP_SUBSYS_COUNT] = {
#include <linux/cgroup_subsys.h>
};
@@ -111,13 +112,13 @@ struct cgroupfs_root {
* The bitmask of subsystems intended to be attached to this
* hierarchy
*/
- unsigned long subsys_bits;
+ unsigned long subsys_mask;
/* Unique id for this hierarchy. */
int hierarchy_id;
/* The bitmask of subsystems currently attached to this hierarchy */
- unsigned long actual_subsys_bits;
+ unsigned long actual_subsys_mask;
/* A list running through the attached subsystems */
struct list_head subsys_list;
@@ -276,7 +277,8 @@ inline int cgroup_is_removed(const struct cgroup *cgrp)
/* bits in struct cgroupfs_root flags field */
enum {
- ROOT_NOPREFIX, /* mounted subsystems have no named prefix */
+ ROOT_NOPREFIX, /* mounted subsystems have no named prefix */
+ ROOT_XATTR, /* supports extended attributes */
};
static int cgroup_is_releasable(const struct cgroup *cgrp)
@@ -556,7 +558,7 @@ static struct css_set *find_existing_css_set(
* won't change, so no need for locking.
*/
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
- if (root->subsys_bits & (1UL << i)) {
+ if (root->subsys_mask & (1UL << i)) {
/* Subsystem is in this hierarchy. So we want
* the subsystem state from the new
* cgroup */
@@ -824,7 +826,8 @@ EXPORT_SYMBOL_GPL(cgroup_unlock);
static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
static struct dentry *cgroup_lookup(struct inode *, struct dentry *, unsigned int);
static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry);
-static int cgroup_populate_dir(struct cgroup *cgrp);
+static int cgroup_populate_dir(struct cgroup *cgrp, bool base_files,
+ unsigned long subsys_mask);
static const struct inode_operations cgroup_dir_inode_operations;
static const struct file_operations proc_cgroupstats_operations;
@@ -912,15 +915,19 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode)
*/
BUG_ON(!list_empty(&cgrp->pidlists));
+ simple_xattrs_free(&cgrp->xattrs);
+
kfree_rcu(cgrp, rcu_head);
} else {
struct cfent *cfe = __d_cfe(dentry);
struct cgroup *cgrp = dentry->d_parent->d_fsdata;
+ struct cftype *cft = cfe->type;
WARN_ONCE(!list_empty(&cfe->node) &&
cgrp != &cgrp->root->top_cgroup,
"cfe still linked for %s\n", cfe->type->name);
kfree(cfe);
+ simple_xattrs_free(&cft->xattrs);
}
iput(inode);
}
@@ -963,12 +970,29 @@ static int cgroup_rm_file(struct cgroup *cgrp, const struct cftype *cft)
return -ENOENT;
}
-static void cgroup_clear_directory(struct dentry *dir)
+/**
+ * cgroup_clear_directory - selective removal of base and subsystem files
+ * @dir: directory containing the files
+ * @base_files: true if the base files should be removed
+ * @subsys_mask: mask of the subsystem ids whose files should be removed
+ */
+static void cgroup_clear_directory(struct dentry *dir, bool base_files,
+ unsigned long subsys_mask)
{
struct cgroup *cgrp = __d_cgrp(dir);
+ struct cgroup_subsys *ss;
- while (!list_empty(&cgrp->files))
- cgroup_rm_file(cgrp, NULL);
+ for_each_subsys(cgrp->root, ss) {
+ struct cftype_set *set;
+ if (!test_bit(ss->subsys_id, &subsys_mask))
+ continue;
+ list_for_each_entry(set, &ss->cftsets, node)
+ cgroup_rm_file(cgrp, set->cfts);
+ }
+ if (base_files) {
+ while (!list_empty(&cgrp->files))
+ cgroup_rm_file(cgrp, NULL);
+ }
}
/*
@@ -977,8 +1001,9 @@ static void cgroup_clear_directory(struct dentry *dir)
static void cgroup_d_remove_dir(struct dentry *dentry)
{
struct dentry *parent;
+ struct cgroupfs_root *root = dentry->d_sb->s_fs_info;
- cgroup_clear_directory(dentry);
+ cgroup_clear_directory(dentry, true, root->subsys_mask);
parent = dentry->d_parent;
spin_lock(&parent->d_lock);
@@ -1022,22 +1047,22 @@ void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css)
* returns an error, no reference counts are touched.
*/
static int rebind_subsystems(struct cgroupfs_root *root,
- unsigned long final_bits)
+ unsigned long final_subsys_mask)
{
- unsigned long added_bits, removed_bits;
+ unsigned long added_mask, removed_mask;
struct cgroup *cgrp = &root->top_cgroup;
int i;
BUG_ON(!mutex_is_locked(&cgroup_mutex));
BUG_ON(!mutex_is_locked(&cgroup_root_mutex));
- removed_bits = root->actual_subsys_bits & ~final_bits;
- added_bits = final_bits & ~root->actual_subsys_bits;
+ removed_mask = root->actual_subsys_mask & ~final_subsys_mask;
+ added_mask = final_subsys_mask & ~root->actual_subsys_mask;
/* Check that any added subsystems are currently free */
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
unsigned long bit = 1UL << i;
struct cgroup_subsys *ss = subsys[i];
- if (!(bit & added_bits))
+ if (!(bit & added_mask))
continue;
/*
* Nobody should tell us to do a subsys that doesn't exist:
@@ -1062,7 +1087,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
unsigned long bit = 1UL << i;
- if (bit & added_bits) {
+ if (bit & added_mask) {
/* We're binding this subsystem to this hierarchy */
BUG_ON(ss == NULL);
BUG_ON(cgrp->subsys[i]);
@@ -1075,7 +1100,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
if (ss->bind)
ss->bind(cgrp);
/* refcount was already taken, and we're keeping it */
- } else if (bit & removed_bits) {
+ } else if (bit & removed_mask) {
/* We're removing this subsystem */
BUG_ON(ss == NULL);
BUG_ON(cgrp->subsys[i] != dummytop->subsys[i]);
@@ -1088,7 +1113,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
list_move(&ss->sibling, &rootnode.subsys_list);
/* subsystem is now free - drop reference on module */
module_put(ss->module);
- } else if (bit & final_bits) {
+ } else if (bit & final_subsys_mask) {
/* Subsystem state should already exist */
BUG_ON(ss == NULL);
BUG_ON(!cgrp->subsys[i]);
@@ -1105,7 +1130,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
BUG_ON(cgrp->subsys[i]);
}
}
- root->subsys_bits = root->actual_subsys_bits = final_bits;
+ root->subsys_mask = root->actual_subsys_mask = final_subsys_mask;
synchronize_rcu();
return 0;
@@ -1121,6 +1146,8 @@ static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry)
seq_printf(seq, ",%s", ss->name);
if (test_bit(ROOT_NOPREFIX, &root->flags))
seq_puts(seq, ",noprefix");
+ if (test_bit(ROOT_XATTR, &root->flags))
+ seq_puts(seq, ",xattr");
if (strlen(root->release_agent_path))
seq_printf(seq, ",release_agent=%s", root->release_agent_path);
if (clone_children(&root->top_cgroup))
@@ -1132,7 +1159,7 @@ static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry)
}
struct cgroup_sb_opts {
- unsigned long subsys_bits;
+ unsigned long subsys_mask;
unsigned long flags;
char *release_agent;
bool clone_children;
@@ -1189,6 +1216,10 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
opts->clone_children = true;
continue;
}
+ if (!strcmp(token, "xattr")) {
+ set_bit(ROOT_XATTR, &opts->flags);
+ continue;
+ }
if (!strncmp(token, "release_agent=", 14)) {
/* Specifying two release agents is forbidden */
if (opts->release_agent)
@@ -1237,7 +1268,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
/* Mutually exclusive option 'all' + subsystem name */
if (all_ss)
return -EINVAL;
- set_bit(i, &opts->subsys_bits);
+ set_bit(i, &opts->subsys_mask);
one_ss = true;
break;
@@ -1258,7 +1289,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
continue;
if (ss->disabled)
continue;
- set_bit(i, &opts->subsys_bits);
+ set_bit(i, &opts->subsys_mask);
}
}
@@ -1270,19 +1301,19 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
* the cpuset subsystem.
*/
if (test_bit(ROOT_NOPREFIX, &opts->flags) &&
- (opts->subsys_bits & mask))
+ (opts->subsys_mask & mask))
return -EINVAL;
/* Can't specify "none" and some subsystems */
- if (opts->subsys_bits && opts->none)
+ if (opts->subsys_mask && opts->none)
return -EINVAL;
/*
* We either have to specify by name or by subsystems. (So all
* empty hierarchies must have a name).
*/
- if (!opts->subsys_bits && !opts->name)
+ if (!opts->subsys_mask && !opts->name)
return -EINVAL;
/*
@@ -1291,10 +1322,10 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
* take duplicate reference counts on a subsystem that's already used,
* but rebind_subsystems handles this case.
*/
- for (i = CGROUP_BUILTIN_SUBSYS_COUNT; i < CGROUP_SUBSYS_COUNT; i++) {
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
unsigned long bit = 1UL << i;
- if (!(bit & opts->subsys_bits))
+ if (!(bit & opts->subsys_mask))
continue;
if (!try_module_get(subsys[i]->module)) {
module_pin_failed = true;
@@ -1307,11 +1338,11 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
* raced with a module_delete call, and to the user this is
* essentially a "subsystem doesn't exist" case.
*/
- for (i--; i >= CGROUP_BUILTIN_SUBSYS_COUNT; i--) {
+ for (i--; i >= 0; i--) {
/* drop refcounts only on the ones we took */
unsigned long bit = 1UL << i;
- if (!(bit & opts->subsys_bits))
+ if (!(bit & opts->subsys_mask))
continue;
module_put(subsys[i]->module);
}
@@ -1321,13 +1352,13 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
return 0;
}
-static void drop_parsed_module_refcounts(unsigned long subsys_bits)
+static void drop_parsed_module_refcounts(unsigned long subsys_mask)
{
int i;
- for (i = CGROUP_BUILTIN_SUBSYS_COUNT; i < CGROUP_SUBSYS_COUNT; i++) {
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
unsigned long bit = 1UL << i;
- if (!(bit & subsys_bits))
+ if (!(bit & subsys_mask))
continue;
module_put(subsys[i]->module);
}
@@ -1339,6 +1370,7 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data)
struct cgroupfs_root *root = sb->s_fs_info;
struct cgroup *cgrp = &root->top_cgroup;
struct cgroup_sb_opts opts;
+ unsigned long added_mask, removed_mask;
mutex_lock(&cgrp->dentry->d_inode->i_mutex);
mutex_lock(&cgroup_mutex);
@@ -1350,27 +1382,31 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data)
goto out_unlock;
/* See feature-removal-schedule.txt */
- if (opts.subsys_bits != root->actual_subsys_bits || opts.release_agent)
+ if (opts.subsys_mask != root->actual_subsys_mask || opts.release_agent)
pr_warning("cgroup: option changes via remount are deprecated (pid=%d comm=%s)\n",
task_tgid_nr(current), current->comm);
+ added_mask = opts.subsys_mask & ~root->subsys_mask;
+ removed_mask = root->subsys_mask & ~opts.subsys_mask;
+
/* Don't allow flags or name to change at remount */
if (opts.flags != root->flags ||
(opts.name && strcmp(opts.name, root->name))) {
ret = -EINVAL;
- drop_parsed_module_refcounts(opts.subsys_bits);
+ drop_parsed_module_refcounts(opts.subsys_mask);
goto out_unlock;
}
- ret = rebind_subsystems(root, opts.subsys_bits);
+ ret = rebind_subsystems(root, opts.subsys_mask);
if (ret) {
- drop_parsed_module_refcounts(opts.subsys_bits);
+ drop_parsed_module_refcounts(opts.subsys_mask);
goto out_unlock;
}
/* clear out any existing files and repopulate subsystem files */
- cgroup_clear_directory(cgrp->dentry);
- cgroup_populate_dir(cgrp);
+ cgroup_clear_directory(cgrp->dentry, false, removed_mask);
+ /* re-populate subsystem files */
+ cgroup_populate_dir(cgrp, false, added_mask);
if (opts.release_agent)
strcpy(root->release_agent_path, opts.release_agent);
@@ -1401,6 +1437,7 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
mutex_init(&cgrp->pidlist_mutex);
INIT_LIST_HEAD(&cgrp->event_list);
spin_lock_init(&cgrp->event_list_lock);
+ simple_xattrs_init(&cgrp->xattrs);
}
static void init_cgroup_root(struct cgroupfs_root *root)
@@ -1455,8 +1492,8 @@ static int cgroup_test_super(struct super_block *sb, void *data)
* If we asked for subsystems (or explicitly for no
* subsystems) then they must match
*/
- if ((opts->subsys_bits || opts->none)
- && (opts->subsys_bits != root->subsys_bits))
+ if ((opts->subsys_mask || opts->none)
+ && (opts->subsys_mask != root->subsys_mask))
return 0;
return 1;
@@ -1466,7 +1503,7 @@ static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts)
{
struct cgroupfs_root *root;
- if (!opts->subsys_bits && !opts->none)
+ if (!opts->subsys_mask && !opts->none)
return NULL;
root = kzalloc(sizeof(*root), GFP_KERNEL);
@@ -1479,7 +1516,7 @@ static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts)
}
init_cgroup_root(root);
- root->subsys_bits = opts->subsys_bits;
+ root->subsys_mask = opts->subsys_mask;
root->flags = opts->flags;
if (opts->release_agent)
strcpy(root->release_agent_path, opts->release_agent);
@@ -1511,7 +1548,7 @@ static int cgroup_set_super(struct super_block *sb, void *data)
if (!opts->new_root)
return -EINVAL;
- BUG_ON(!opts->subsys_bits && !opts->none);
+ BUG_ON(!opts->subsys_mask && !opts->none);
ret = set_anon_super(sb, NULL);
if (ret)
@@ -1629,7 +1666,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
if (ret)
goto unlock_drop;
- ret = rebind_subsystems(root, root->subsys_bits);
+ ret = rebind_subsystems(root, root->subsys_mask);
if (ret == -EBUSY) {
free_cg_links(&tmp_cg_links);
goto unlock_drop;
@@ -1669,7 +1706,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
BUG_ON(root->number_of_cgroups != 1);
cred = override_creds(&init_cred);
- cgroup_populate_dir(root_cgrp);
+ cgroup_populate_dir(root_cgrp, true, root->subsys_mask);
revert_creds(cred);
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&cgroup_mutex);
@@ -1681,7 +1718,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
*/
cgroup_drop_root(opts.new_root);
/* no subsys rebinding, so refcounts don't change */
- drop_parsed_module_refcounts(opts.subsys_bits);
+ drop_parsed_module_refcounts(opts.subsys_mask);
}
kfree(opts.release_agent);
@@ -1695,7 +1732,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
drop_new_super:
deactivate_locked_super(sb);
drop_modules:
- drop_parsed_module_refcounts(opts.subsys_bits);
+ drop_parsed_module_refcounts(opts.subsys_mask);
out_err:
kfree(opts.release_agent);
kfree(opts.name);
@@ -1745,6 +1782,8 @@ static void cgroup_kill_sb(struct super_block *sb) {
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&cgroup_mutex);
+ simple_xattrs_free(&cgrp->xattrs);
+
kill_litter_super(sb);
cgroup_drop_root(root);
}
@@ -2551,6 +2590,64 @@ static int cgroup_rename(struct inode *old_dir, struct dentry *old_dentry,
return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
}
+static struct simple_xattrs *__d_xattrs(struct dentry *dentry)
+{
+ if (S_ISDIR(dentry->d_inode->i_mode))
+ return &__d_cgrp(dentry)->xattrs;
+ else
+ return &__d_cft(dentry)->xattrs;
+}
+
+static inline int xattr_enabled(struct dentry *dentry)
+{
+ struct cgroupfs_root *root = dentry->d_sb->s_fs_info;
+ return test_bit(ROOT_XATTR, &root->flags);
+}
+
+static bool is_valid_xattr(const char *name)
+{
+ if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
+ !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN))
+ return true;
+ return false;
+}
+
+static int cgroup_setxattr(struct dentry *dentry, const char *name,
+ const void *val, size_t size, int flags)
+{
+ if (!xattr_enabled(dentry))
+ return -EOPNOTSUPP;
+ if (!is_valid_xattr(name))
+ return -EINVAL;
+ return simple_xattr_set(__d_xattrs(dentry), name, val, size, flags);
+}
+
+static int cgroup_removexattr(struct dentry *dentry, const char *name)
+{
+ if (!xattr_enabled(dentry))
+ return -EOPNOTSUPP;
+ if (!is_valid_xattr(name))
+ return -EINVAL;
+ return simple_xattr_remove(__d_xattrs(dentry), name);
+}
+
+static ssize_t cgroup_getxattr(struct dentry *dentry, const char *name,
+ void *buf, size_t size)
+{
+ if (!xattr_enabled(dentry))
+ return -EOPNOTSUPP;
+ if (!is_valid_xattr(name))
+ return -EINVAL;
+ return simple_xattr_get(__d_xattrs(dentry), name, buf, size);
+}
+
+static ssize_t cgroup_listxattr(struct dentry *dentry, char *buf, size_t size)
+{
+ if (!xattr_enabled(dentry))
+ return -EOPNOTSUPP;
+ return simple_xattr_list(__d_xattrs(dentry), buf, size);
+}
+
static const struct file_operations cgroup_file_operations = {
.read = cgroup_file_read,
.write = cgroup_file_write,
@@ -2559,11 +2656,22 @@ static const struct file_operations cgroup_file_operations = {
.release = cgroup_file_release,
};
+static const struct inode_operations cgroup_file_inode_operations = {
+ .setxattr = cgroup_setxattr,
+ .getxattr = cgroup_getxattr,
+ .listxattr = cgroup_listxattr,
+ .removexattr = cgroup_removexattr,
+};
+
static const struct inode_operations cgroup_dir_inode_operations = {
.lookup = cgroup_lookup,
.mkdir = cgroup_mkdir,
.rmdir = cgroup_rmdir,
.rename = cgroup_rename,
+ .setxattr = cgroup_setxattr,
+ .getxattr = cgroup_getxattr,
+ .listxattr = cgroup_listxattr,
+ .removexattr = cgroup_removexattr,
};
static struct dentry *cgroup_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
@@ -2611,6 +2719,7 @@ static int cgroup_create_file(struct dentry *dentry, umode_t mode,
} else if (S_ISREG(mode)) {
inode->i_size = 0;
inode->i_fop = &cgroup_file_operations;
+ inode->i_op = &cgroup_file_inode_operations;
}
d_instantiate(dentry, inode);
dget(dentry); /* Extra count - pin the dentry in core */
@@ -2671,7 +2780,7 @@ static umode_t cgroup_file_mode(const struct cftype *cft)
}
static int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys,
- const struct cftype *cft)
+ struct cftype *cft)
{
struct dentry *dir = cgrp->dentry;
struct cgroup *parent = __d_cgrp(dir);
@@ -2681,6 +2790,8 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys,
umode_t mode;
char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 };
+ simple_xattrs_init(&cft->xattrs);
+
/* does @cft->flags tell us to skip creation on @cgrp? */
if ((cft->flags & CFTYPE_NOT_ON_ROOT) && !cgrp->parent)
return 0;
@@ -2721,9 +2832,9 @@ out:
}
static int cgroup_addrm_files(struct cgroup *cgrp, struct cgroup_subsys *subsys,
- const struct cftype cfts[], bool is_add)
+ struct cftype cfts[], bool is_add)
{
- const struct cftype *cft;
+ struct cftype *cft;
int err, ret = 0;
for (cft = cfts; cft->name[0] != '\0'; cft++) {
@@ -2757,7 +2868,7 @@ static void cgroup_cfts_prepare(void)
}
static void cgroup_cfts_commit(struct cgroup_subsys *ss,
- const struct cftype *cfts, bool is_add)
+ struct cftype *cfts, bool is_add)
__releases(&cgroup_mutex) __releases(&cgroup_cft_mutex)
{
LIST_HEAD(pending);
@@ -2808,7 +2919,7 @@ static void cgroup_cfts_commit(struct cgroup_subsys *ss,
* function currently returns 0 as long as @cfts registration is successful
* even if some file creation attempts on existing cgroups fail.
*/
-int cgroup_add_cftypes(struct cgroup_subsys *ss, const struct cftype *cfts)
+int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
struct cftype_set *set;
@@ -2838,7 +2949,7 @@ EXPORT_SYMBOL_GPL(cgroup_add_cftypes);
* Returns 0 on successful unregistration, -ENOENT if @cfts is not
* registered with @ss.
*/
-int cgroup_rm_cftypes(struct cgroup_subsys *ss, const struct cftype *cfts)
+int cgroup_rm_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
struct cftype_set *set;
@@ -3843,18 +3954,29 @@ static struct cftype files[] = {
{ } /* terminate */
};
-static int cgroup_populate_dir(struct cgroup *cgrp)
+/**
+ * cgroup_populate_dir - selectively creation of files in a directory
+ * @cgrp: target cgroup
+ * @base_files: true if the base files should be added
+ * @subsys_mask: mask of the subsystem ids whose files should be added
+ */
+static int cgroup_populate_dir(struct cgroup *cgrp, bool base_files,
+ unsigned long subsys_mask)
{
int err;
struct cgroup_subsys *ss;
- err = cgroup_addrm_files(cgrp, NULL, files, true);
- if (err < 0)
- return err;
+ if (base_files) {
+ err = cgroup_addrm_files(cgrp, NULL, files, true);
+ if (err < 0)
+ return err;
+ }
/* process cftsets of each subsystem */
for_each_subsys(cgrp->root, ss) {
struct cftype_set *set;
+ if (!test_bit(ss->subsys_id, &subsys_mask))
+ continue;
list_for_each_entry(set, &ss->cftsets, node)
cgroup_addrm_files(cgrp, ss, set->cfts, true);
@@ -3988,7 +4110,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
list_add_tail(&cgrp->allcg_node, &root->allcg_list);
- err = cgroup_populate_dir(cgrp);
+ err = cgroup_populate_dir(cgrp, true, root->subsys_mask);
/* If err < 0, we have a half-filled directory - oh well ;) */
mutex_unlock(&cgroup_mutex);
@@ -4321,8 +4443,7 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
* since cgroup_init_subsys will have already taken care of it.
*/
if (ss->module == NULL) {
- /* a few sanity checks */
- BUG_ON(ss->subsys_id >= CGROUP_BUILTIN_SUBSYS_COUNT);
+ /* a sanity check */
BUG_ON(subsys[ss->subsys_id] != ss);
return 0;
}
@@ -4330,24 +4451,8 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
/* init base cftset */
cgroup_init_cftsets(ss);
- /*
- * need to register a subsys id before anything else - for example,
- * init_cgroup_css needs it.
- */
mutex_lock(&cgroup_mutex);
- /* find the first empty slot in the array */
- for (i = CGROUP_BUILTIN_SUBSYS_COUNT; i < CGROUP_SUBSYS_COUNT; i++) {
- if (subsys[i] == NULL)
- break;
- }
- if (i == CGROUP_SUBSYS_COUNT) {
- /* maximum number of subsystems already registered! */
- mutex_unlock(&cgroup_mutex);
- return -EBUSY;
- }
- /* assign ourselves the subsys_id */
- ss->subsys_id = i;
- subsys[i] = ss;
+ subsys[ss->subsys_id] = ss;
/*
* no ss->create seems to need anything important in the ss struct, so
@@ -4356,7 +4461,7 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
css = ss->create(dummytop);
if (IS_ERR(css)) {
/* failure case - need to deassign the subsys[] slot. */
- subsys[i] = NULL;
+ subsys[ss->subsys_id] = NULL;
mutex_unlock(&cgroup_mutex);
return PTR_ERR(css);
}
@@ -4372,7 +4477,7 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
if (ret) {
dummytop->subsys[ss->subsys_id] = NULL;
ss->destroy(dummytop);
- subsys[i] = NULL;
+ subsys[ss->subsys_id] = NULL;
mutex_unlock(&cgroup_mutex);
return ret;
}
@@ -4439,7 +4544,6 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss)
mutex_lock(&cgroup_mutex);
/* deassign the subsys_id */
- BUG_ON(ss->subsys_id < CGROUP_BUILTIN_SUBSYS_COUNT);
subsys[ss->subsys_id] = NULL;
/* remove subsystem from rootnode's list of subsystems */
@@ -4502,10 +4606,13 @@ int __init cgroup_init_early(void)
for (i = 0; i < CSS_SET_TABLE_SIZE; i++)
INIT_HLIST_HEAD(&css_set_table[i]);
- /* at bootup time, we don't worry about modular subsystems */
- for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
+ /* at bootup time, we don't worry about modular subsystems */
+ if (!ss || ss->module)
+ continue;
+
BUG_ON(!ss->name);
BUG_ON(strlen(ss->name) > MAX_CGROUP_TYPE_NAMELEN);
BUG_ON(!ss->create);
@@ -4538,9 +4645,12 @@ int __init cgroup_init(void)
if (err)
return err;
- /* at bootup time, we don't worry about modular subsystems */
- for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
+
+ /* at bootup time, we don't worry about modular subsystems */
+ if (!ss || ss->module)
+ continue;
if (!ss->early_init)
cgroup_init_subsys(ss);
if (ss->use_id)
@@ -4735,13 +4845,16 @@ void cgroup_fork_callbacks(struct task_struct *child)
{
if (need_forkexit_callback) {
int i;
- /*
- * forkexit callbacks are only supported for builtin
- * subsystems, and the builtin section of the subsys array is
- * immutable, so we don't need to lock the subsys array here.
- */
- for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
+
+ /*
+ * forkexit callbacks are only supported for
+ * builtin subsystems.
+ */
+ if (!ss || ss->module)
+ continue;
+
if (ss->fork)
ss->fork(child);
}
@@ -4846,12 +4959,13 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
tsk->cgroups = &init_css_set;
if (run_callbacks && need_forkexit_callback) {
- /*
- * modular subsystems can't use callbacks, so no need to lock
- * the subsys array
- */
- for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
+
+ /* modular subsystems can't use callbacks */
+ if (!ss || ss->module)
+ continue;
+
if (ss->exit) {
struct cgroup *old_cgrp =
rcu_dereference_raw(cg->subsys[i])->cgroup;
@@ -5037,13 +5151,17 @@ static int __init cgroup_disable(char *str)
while ((token = strsep(&str, ",")) != NULL) {
if (!*token)
continue;
- /*
- * cgroup_disable, being at boot time, can't know about module
- * subsystems, so we don't worry about them.
- */
- for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
+ /*
+ * cgroup_disable, being at boot time, can't
+ * know about module subsystems, so we don't
+ * worry about them.
+ */
+ if (!ss || ss->module)
+ continue;
+
if (!strcmp(token, ss->name)) {
ss->disabled = 1;
printk(KERN_INFO "Disabling %s control group"