#include <linux/delayacct.h>
#include <linux/cgroupstats.h>
#include <linux/hash.h>
+#include <linux/namei.h>
#include <asm/atomic.h>
/* Hierarchy-specific flags */
unsigned long flags;
- /* The path to use for release notifications. No locking
- * between setting and use - so if userspace updates this
- * while child cgroups exist, you could miss a
- * notification. We ensure that it's always a valid
- * NUL-terminated string */
+ /* The path to use for release notifications. */
char release_agent_path[PATH_MAX];
};
* extra work in the fork/exit path if none of the subsystems need to
* be called.
*/
-static int need_forkexit_callback;
+static int need_forkexit_callback __read_mostly;
static int need_mm_owner_callback __read_mostly;
/* convenient tests for these bits */
* task until after the first call to cgroup_iter_start(). This
* reduces the fork()/exit() overhead for people who have cgroups
* compiled into their kernel but not actually in use */
-static int use_task_css_set_links;
+static int use_task_css_set_links __read_mostly;
/* When we create or destroy a css_set, the operation simply
* takes/releases a reference count on all the cgroups referenced
struct cg_cgroup_link *link;
struct cg_cgroup_link *saved_link;
- write_lock(&css_set_lock);
hlist_del(&cg->hlist);
css_set_count--;
list_del(&link->cgrp_link_list);
kfree(link);
}
-
- write_unlock(&css_set_lock);
}
-static void __release_css_set(struct kref *k, int taskexit)
+static void __put_css_set(struct css_set *cg, int taskexit)
{
int i;
- struct css_set *cg = container_of(k, struct css_set, ref);
-
+ /*
+ * Ensure that the refcount doesn't hit zero while any readers
+ * can see it. Similar to atomic_dec_and_lock(), but for an
+ * rwlock
+ */
+ if (atomic_add_unless(&cg->refcount, -1, 1))
+ return;
+ write_lock(&css_set_lock);
+ if (!atomic_dec_and_test(&cg->refcount)) {
+ write_unlock(&css_set_lock);
+ return;
+ }
unlink_css_set(cg);
+ write_unlock(&css_set_lock);
rcu_read_lock();
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
kfree(cg);
}
-static void release_css_set(struct kref *k)
-{
- __release_css_set(k, 0);
-}
-
-static void release_css_set_taskexit(struct kref *k)
-{
- __release_css_set(k, 1);
-}
-
/*
* refcounted get/put for css_set objects
*/
static inline void get_css_set(struct css_set *cg)
{
- kref_get(&cg->ref);
+ atomic_inc(&cg->refcount);
}
static inline void put_css_set(struct css_set *cg)
{
- kref_put(&cg->ref, release_css_set);
+ __put_css_set(cg, 0);
}
static inline void put_css_set_taskexit(struct css_set *cg)
{
- kref_put(&cg->ref, release_css_set_taskexit);
+ __put_css_set(cg, 1);
}
/*
return NULL;
}
+static void free_cg_links(struct list_head *tmp)
+{
+ struct cg_cgroup_link *link;
+ struct cg_cgroup_link *saved_link;
+
+ list_for_each_entry_safe(link, saved_link, tmp, cgrp_link_list) {
+ list_del(&link->cgrp_link_list);
+ kfree(link);
+ }
+}
+
/*
* allocate_cg_links() allocates "count" cg_cgroup_link structures
* and chains them on tmp through their cgrp_link_list fields. Returns 0 on
static int allocate_cg_links(int count, struct list_head *tmp)
{
struct cg_cgroup_link *link;
- struct cg_cgroup_link *saved_link;
int i;
INIT_LIST_HEAD(tmp);
for (i = 0; i < count; i++) {
link = kmalloc(sizeof(*link), GFP_KERNEL);
if (!link) {
- list_for_each_entry_safe(link, saved_link, tmp,
- cgrp_link_list) {
- list_del(&link->cgrp_link_list);
- kfree(link);
- }
+ free_cg_links(tmp);
return -ENOMEM;
}
list_add(&link->cgrp_link_list, tmp);
return 0;
}
-static void free_cg_links(struct list_head *tmp)
-{
- struct cg_cgroup_link *link;
- struct cg_cgroup_link *saved_link;
-
- list_for_each_entry_safe(link, saved_link, tmp, cgrp_link_list) {
- list_del(&link->cgrp_link_list);
- kfree(link);
- }
-}
-
/*
* find_css_set() takes an existing cgroup group and a
* cgroup object, and returns a css_set object that's
return NULL;
}
- kref_init(&res->ref);
+ atomic_set(&res->refcount, 1);
INIT_LIST_HEAD(&res->cg_links);
INIT_LIST_HEAD(&res->tasks);
INIT_HLIST_NODE(&res->hlist);
* knows that the cgroup won't be removed, as cgroup_rmdir()
* needs that mutex.
*
- * The cgroup_common_file_write handler for operations that modify
- * the cgroup hierarchy holds cgroup_mutex across the entire operation,
- * single threading all such cgroup modifications across the system.
- *
* The fork and exit callbacks cgroup_fork() and cgroup_exit(), don't
* (usually) take cgroup_mutex. These are the two most performance
* critical pieces of code here. The exception occurs on cgroup_exit(),
.remount_fs = cgroup_remount,
};
+static void init_cgroup_housekeeping(struct cgroup *cgrp)
+{
+ INIT_LIST_HEAD(&cgrp->sibling);
+ INIT_LIST_HEAD(&cgrp->children);
+ INIT_LIST_HEAD(&cgrp->css_sets);
+ INIT_LIST_HEAD(&cgrp->release_list);
+ init_rwsem(&cgrp->pids_mutex);
+}
static void init_cgroup_root(struct cgroupfs_root *root)
{
struct cgroup *cgrp = &root->top_cgroup;
root->number_of_cgroups = 1;
cgrp->root = root;
cgrp->top_cgroup = cgrp;
- INIT_LIST_HEAD(&cgrp->sibling);
- INIT_LIST_HEAD(&cgrp->children);
- INIT_LIST_HEAD(&cgrp->css_sets);
- INIT_LIST_HEAD(&cgrp->release_list);
+ init_cgroup_housekeeping(cgrp);
}
static int cgroup_test_super(struct super_block *sb, void *data)
struct super_block *sb;
struct cgroupfs_root *root;
struct list_head tmp_cg_links;
- INIT_LIST_HEAD(&tmp_cg_links);
/* First find the desired set of subsystems */
ret = parse_cgroupfs_options(data, &opts);
}
/*
- * Attach task with pid 'pid' to cgroup 'cgrp'. Call with
- * cgroup_mutex, may take task_lock of task
+ * Attach task with pid 'pid' to cgroup 'cgrp'. Call with cgroup_mutex
+ * held. May take task_lock of task
*/
-static int attach_task_by_pid(struct cgroup *cgrp, char *pidbuf)
+static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
{
- pid_t pid;
struct task_struct *tsk;
int ret;
- if (sscanf(pidbuf, "%d", &pid) != 1)
- return -EIO;
-
if (pid) {
rcu_read_lock();
tsk = find_task_by_vpid(pid);
return ret;
}
+static int cgroup_tasks_write(struct cgroup *cgrp, struct cftype *cft, u64 pid)
+{
+ int ret;
+ if (!cgroup_lock_live_group(cgrp))
+ return -ENODEV;
+ ret = attach_task_by_pid(cgrp, pid);
+ cgroup_unlock();
+ return ret;
+}
+
/* The various types of files and directories in a cgroup file system */
enum cgroup_filetype {
FILE_ROOT,
FILE_RELEASE_AGENT,
};
+/**
+ * cgroup_lock_live_group - take cgroup_mutex and check that cgrp is alive.
+ * @cgrp: the cgroup to be checked for liveness
+ *
+ * On success, returns true; the lock should be later released with
+ * cgroup_unlock(). On failure returns false with no lock held.
+ */
+bool cgroup_lock_live_group(struct cgroup *cgrp)
+{
+ mutex_lock(&cgroup_mutex);
+ if (cgroup_is_removed(cgrp)) {
+ mutex_unlock(&cgroup_mutex);
+ return false;
+ }
+ return true;
+}
+
+static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft,
+ const char *buffer)
+{
+ BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
+ if (!cgroup_lock_live_group(cgrp))
+ return -ENODEV;
+ strcpy(cgrp->root->release_agent_path, buffer);
+ cgroup_unlock();
+ return 0;
+}
+
+static int cgroup_release_agent_show(struct cgroup *cgrp, struct cftype *cft,
+ struct seq_file *seq)
+{
+ if (!cgroup_lock_live_group(cgrp))
+ return -ENODEV;
+ seq_puts(seq, cgrp->root->release_agent_path);
+ seq_putc(seq, '\n');
+ cgroup_unlock();
+ return 0;
+}
+
+/* A buffer size big enough for numbers or short strings */
+#define CGROUP_LOCAL_BUFFER_SIZE 64
+
static ssize_t cgroup_write_X64(struct cgroup *cgrp, struct cftype *cft,
struct file *file,
const char __user *userbuf,
size_t nbytes, loff_t *unused_ppos)
{
- char buffer[64];
+ char buffer[CGROUP_LOCAL_BUFFER_SIZE];
int retval = 0;
char *end;
return retval;
}
-static ssize_t cgroup_common_file_write(struct cgroup *cgrp,
- struct cftype *cft,
- struct file *file,
- const char __user *userbuf,
- size_t nbytes, loff_t *unused_ppos)
+static ssize_t cgroup_write_string(struct cgroup *cgrp, struct cftype *cft,
+ struct file *file,
+ const char __user *userbuf,
+ size_t nbytes, loff_t *unused_ppos)
{
- enum cgroup_filetype type = cft->private;
- char *buffer;
+ char local_buffer[CGROUP_LOCAL_BUFFER_SIZE];
int retval = 0;
+ size_t max_bytes = cft->max_write_len;
+ char *buffer = local_buffer;
- if (nbytes >= PATH_MAX)
+ if (!max_bytes)
+ max_bytes = sizeof(local_buffer) - 1;
+ if (nbytes >= max_bytes)
return -E2BIG;
-
- /* +1 for nul-terminator */
- buffer = kmalloc(nbytes + 1, GFP_KERNEL);
- if (buffer == NULL)
- return -ENOMEM;
-
- if (copy_from_user(buffer, userbuf, nbytes)) {
+ /* Allocate a dynamic buffer if we need one */
+ if (nbytes >= sizeof(local_buffer)) {
+ buffer = kmalloc(nbytes + 1, GFP_KERNEL);
+ if (buffer == NULL)
+ return -ENOMEM;
+ }
+ if (nbytes && copy_from_user(buffer, userbuf, nbytes)) {
retval = -EFAULT;
- goto out1;
+ goto out;
}
- buffer[nbytes] = 0; /* nul-terminate */
- strstrip(buffer); /* strip -just- trailing whitespace */
-
- mutex_lock(&cgroup_mutex);
- /*
- * This was already checked for in cgroup_file_write(), but
- * check again now we're holding cgroup_mutex.
- */
- if (cgroup_is_removed(cgrp)) {
- retval = -ENODEV;
- goto out2;
- }
-
- switch (type) {
- case FILE_TASKLIST:
- retval = attach_task_by_pid(cgrp, buffer);
- break;
- case FILE_NOTIFY_ON_RELEASE:
- clear_bit(CGRP_RELEASABLE, &cgrp->flags);
- if (simple_strtoul(buffer, NULL, 10) != 0)
- set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
- else
- clear_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
- break;
- case FILE_RELEASE_AGENT:
- BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
- strcpy(cgrp->root->release_agent_path, buffer);
- break;
- default:
- retval = -EINVAL;
- goto out2;
- }
-
- if (retval == 0)
+ buffer[nbytes] = 0; /* nul-terminate */
+ strstrip(buffer);
+ retval = cft->write_string(cgrp, cft, buffer);
+ if (!retval)
retval = nbytes;
-out2:
- mutex_unlock(&cgroup_mutex);
-out1:
- kfree(buffer);
+out:
+ if (buffer != local_buffer)
+ kfree(buffer);
return retval;
}
return cft->write(cgrp, cft, file, buf, nbytes, ppos);
if (cft->write_u64 || cft->write_s64)
return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos);
+ if (cft->write_string)
+ return cgroup_write_string(cgrp, cft, file, buf, nbytes, ppos);
if (cft->trigger) {
int ret = cft->trigger(cgrp, (unsigned int)cft->private);
return ret ? ret : nbytes;
char __user *buf, size_t nbytes,
loff_t *ppos)
{
- char tmp[64];
+ char tmp[CGROUP_LOCAL_BUFFER_SIZE];
u64 val = cft->read_u64(cgrp, cft);
int len = sprintf(tmp, "%llu\n", (unsigned long long) val);
char __user *buf, size_t nbytes,
loff_t *ppos)
{
- char tmp[64];
+ char tmp[CGROUP_LOCAL_BUFFER_SIZE];
s64 val = cft->read_s64(cgrp, cft);
int len = sprintf(tmp, "%lld\n", (long long) val);
return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
}
-static ssize_t cgroup_common_file_read(struct cgroup *cgrp,
- struct cftype *cft,
- struct file *file,
- char __user *buf,
- size_t nbytes, loff_t *ppos)
-{
- enum cgroup_filetype type = cft->private;
- char *page;
- ssize_t retval = 0;
- char *s;
-
- if (!(page = (char *)__get_free_page(GFP_KERNEL)))
- return -ENOMEM;
-
- s = page;
-
- switch (type) {
- case FILE_RELEASE_AGENT:
- {
- struct cgroupfs_root *root;
- size_t n;
- mutex_lock(&cgroup_mutex);
- root = cgrp->root;
- n = strnlen(root->release_agent_path,
- sizeof(root->release_agent_path));
- n = min(n, (size_t) PAGE_SIZE);
- strncpy(s, root->release_agent_path, n);
- mutex_unlock(&cgroup_mutex);
- s += n;
- break;
- }
- default:
- retval = -EINVAL;
- goto out;
- }
- *s++ = '\n';
-
- retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
-out:
- free_page((unsigned long)page);
- return retval;
-}
-
static ssize_t cgroup_file_read(struct file *file, char __user *buf,
size_t nbytes, loff_t *ppos)
{
return cft->read_seq_string(state->cgroup, cft, m);
}
-int cgroup_seqfile_release(struct inode *inode, struct file *file)
+static int cgroup_seqfile_release(struct inode *inode, struct file *file)
{
struct seq_file *seq = file->private_data;
kfree(seq->private);
static struct file_operations cgroup_seqfile_operations = {
.read = seq_read,
+ .write = cgroup_file_write,
.llseek = seq_lseek,
.release = cgroup_seqfile_release,
};
read_lock(&css_set_lock);
list_for_each_entry(link, &cgrp->css_sets, cgrp_link_list) {
- count += atomic_read(&link->cg->ref.refcount);
+ count += atomic_read(&link->cg->refcount);
}
read_unlock(&css_set_lock);
return count;
* but we cannot guarantee that the information we produce is correct
* unless we produce it entirely atomically.
*
- * Upon tasks file open(), a struct ctr_struct is allocated, that
- * will have a pointer to an array (also allocated here). The struct
- * ctr_struct * is stored in file->private_data. Its resources will
- * be freed by release() when the file is closed. The array is used
- * to sprintf the PIDs and then used by read().
*/
-struct ctr_struct {
- char *buf;
- int bufsz;
-};
/*
* Load into 'pidarray' up to 'npids' of the tasks using cgroup
struct cgroup *cgrp;
struct cgroup_iter it;
struct task_struct *tsk;
+
/*
- * Validate dentry by checking the superblock operations
+ * Validate dentry by checking the superblock operations,
+ * and make sure it's a directory.
*/
- if (dentry->d_sb->s_op != &cgroup_ops)
+ if (dentry->d_sb->s_op != &cgroup_ops ||
+ !S_ISDIR(dentry->d_inode->i_mode))
goto err;
ret = 0;
return *(pid_t *)a - *(pid_t *)b;
}
+
/*
- * Convert array 'a' of 'npids' pid_t's to a string of newline separated
- * decimal pids in 'buf'. Don't write more than 'sz' chars, but return
- * count 'cnt' of how many chars would be written if buf were large enough.
+ * seq_file methods for the "tasks" file. The seq_file position is the
+ * next pid to display; the seq_file iterator is a pointer to the pid
+ * in the cgroup->tasks_pids array.
*/
-static int pid_array_to_buf(char *buf, int sz, pid_t *a, int npids)
+
+static void *cgroup_tasks_start(struct seq_file *s, loff_t *pos)
{
- int cnt = 0;
- int i;
+ /*
+ * Initially we receive a position value that corresponds to
+ * one more than the last pid shown (or 0 on the first call or
+ * after a seek to the start). Use a binary-search to find the
+ * next pid to display, if any
+ */
+ struct cgroup *cgrp = s->private;
+ int index = 0, pid = *pos;
+ int *iter;
+
+ down_read(&cgrp->pids_mutex);
+ if (pid) {
+ int end = cgrp->pids_length;
+
+ while (index < end) {
+ int mid = (index + end) / 2;
+ if (cgrp->tasks_pids[mid] == pid) {
+ index = mid;
+ break;
+ } else if (cgrp->tasks_pids[mid] <= pid)
+ index = mid + 1;
+ else
+ end = mid;
+ }
+ }
+ /* If we're off the end of the array, we're done */
+ if (index >= cgrp->pids_length)
+ return NULL;
+ /* Update the abstract position to be the actual pid that we found */
+ iter = cgrp->tasks_pids + index;
+ *pos = *iter;
+ return iter;
+}
+
+static void cgroup_tasks_stop(struct seq_file *s, void *v)
+{
+ struct cgroup *cgrp = s->private;
+ up_read(&cgrp->pids_mutex);
+}
+
+static void *cgroup_tasks_next(struct seq_file *s, void *v, loff_t *pos)
+{
+ struct cgroup *cgrp = s->private;
+ int *p = v;
+ int *end = cgrp->tasks_pids + cgrp->pids_length;
+
+ /*
+ * Advance to the next pid in the array. If this goes off the
+ * end, we're done
+ */
+ p++;
+ if (p >= end) {
+ return NULL;
+ } else {
+ *pos = *p;
+ return p;
+ }
+}
+
+static int cgroup_tasks_show(struct seq_file *s, void *v)
+{
+ return seq_printf(s, "%d\n", *(int *)v);
+}
+
+static struct seq_operations cgroup_tasks_seq_operations = {
+ .start = cgroup_tasks_start,
+ .stop = cgroup_tasks_stop,
+ .next = cgroup_tasks_next,
+ .show = cgroup_tasks_show,
+};
+
+static void release_cgroup_pid_array(struct cgroup *cgrp)
+{
+ down_write(&cgrp->pids_mutex);
+ BUG_ON(!cgrp->pids_use_count);
+ if (!--cgrp->pids_use_count) {
+ kfree(cgrp->tasks_pids);
+ cgrp->tasks_pids = NULL;
+ cgrp->pids_length = 0;
+ }
+ up_write(&cgrp->pids_mutex);
+}
+
+static int cgroup_tasks_release(struct inode *inode, struct file *file)
+{
+ struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
+
+ if (!(file->f_mode & FMODE_READ))
+ return 0;
- for (i = 0; i < npids; i++)
- cnt += snprintf(buf + cnt, max(sz - cnt, 0), "%d\n", a[i]);
- return cnt;
+ release_cgroup_pid_array(cgrp);
+ return seq_release(inode, file);
}
+static struct file_operations cgroup_tasks_operations = {
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .write = cgroup_file_write,
+ .release = cgroup_tasks_release,
+};
+
/*
- * Handle an open on 'tasks' file. Prepare a buffer listing the
+ * Handle an open on 'tasks' file. Prepare an array containing the
* process id's of tasks currently attached to the cgroup being opened.
- *
- * Does not require any specific cgroup mutexes, and does not take any.
*/
+
static int cgroup_tasks_open(struct inode *unused, struct file *file)
{
struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
- struct ctr_struct *ctr;
pid_t *pidarray;
int npids;
- char c;
+ int retval;
+ /* Nothing to do for write-only files */
if (!(file->f_mode & FMODE_READ))
return 0;
- ctr = kmalloc(sizeof(*ctr), GFP_KERNEL);
- if (!ctr)
- goto err0;
-
/*
* If cgroup gets more users after we read count, we won't have
* enough space - tough. This race is indistinguishable to the
* show up until sometime later on.
*/
npids = cgroup_task_count(cgrp);
- if (npids) {
- pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL);
- if (!pidarray)
- goto err1;
-
- npids = pid_array_load(pidarray, npids, cgrp);
- sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
-
- /* Call pid_array_to_buf() twice, first just to get bufsz */
- ctr->bufsz = pid_array_to_buf(&c, sizeof(c), pidarray, npids) + 1;
- ctr->buf = kmalloc(ctr->bufsz, GFP_KERNEL);
- if (!ctr->buf)
- goto err2;
- ctr->bufsz = pid_array_to_buf(ctr->buf, ctr->bufsz, pidarray, npids);
-
- kfree(pidarray);
- } else {
- ctr->buf = NULL;
- ctr->bufsz = 0;
- }
- file->private_data = ctr;
- return 0;
-
-err2:
- kfree(pidarray);
-err1:
- kfree(ctr);
-err0:
- return -ENOMEM;
-}
-
-static ssize_t cgroup_tasks_read(struct cgroup *cgrp,
- struct cftype *cft,
- struct file *file, char __user *buf,
- size_t nbytes, loff_t *ppos)
-{
- struct ctr_struct *ctr = file->private_data;
+ pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL);
+ if (!pidarray)
+ return -ENOMEM;
+ npids = pid_array_load(pidarray, npids, cgrp);
+ sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
- return simple_read_from_buffer(buf, nbytes, ppos, ctr->buf, ctr->bufsz);
-}
+ /*
+ * Store the array in the cgroup, freeing the old
+ * array if necessary
+ */
+ down_write(&cgrp->pids_mutex);
+ kfree(cgrp->tasks_pids);
+ cgrp->tasks_pids = pidarray;
+ cgrp->pids_length = npids;
+ cgrp->pids_use_count++;
+ up_write(&cgrp->pids_mutex);
-static int cgroup_tasks_release(struct inode *unused_inode,
- struct file *file)
-{
- struct ctr_struct *ctr;
+ file->f_op = &cgroup_tasks_operations;
- if (file->f_mode & FMODE_READ) {
- ctr = file->private_data;
- kfree(ctr->buf);
- kfree(ctr);
+ retval = seq_open(file, &cgroup_tasks_seq_operations);
+ if (retval) {
+ release_cgroup_pid_array(cgrp);
+ return retval;
}
+ ((struct seq_file *)file->private_data)->private = cgrp;
return 0;
}
return notify_on_release(cgrp);
}
+static int cgroup_write_notify_on_release(struct cgroup *cgrp,
+ struct cftype *cft,
+ u64 val)
+{
+ clear_bit(CGRP_RELEASABLE, &cgrp->flags);
+ if (val)
+ set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+ else
+ clear_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+ return 0;
+}
+
/*
* for the common functions, 'private' gives the type of file
*/
{
.name = "tasks",
.open = cgroup_tasks_open,
- .read = cgroup_tasks_read,
- .write = cgroup_common_file_write,
+ .write_u64 = cgroup_tasks_write,
.release = cgroup_tasks_release,
.private = FILE_TASKLIST,
},
{
.name = "notify_on_release",
.read_u64 = cgroup_read_notify_on_release,
- .write = cgroup_common_file_write,
+ .write_u64 = cgroup_write_notify_on_release,
.private = FILE_NOTIFY_ON_RELEASE,
},
};
static struct cftype cft_release_agent = {
.name = "release_agent",
- .read = cgroup_common_file_read,
- .write = cgroup_common_file_write,
+ .read_seq_string = cgroup_release_agent_show,
+ .write_string = cgroup_release_agent_write,
+ .max_write_len = PATH_MAX,
.private = FILE_RELEASE_AGENT,
};
mutex_lock(&cgroup_mutex);
- INIT_LIST_HEAD(&cgrp->sibling);
- INIT_LIST_HEAD(&cgrp->children);
- INIT_LIST_HEAD(&cgrp->css_sets);
- INIT_LIST_HEAD(&cgrp->release_list);
+ init_cgroup_housekeeping(cgrp);
cgrp->parent = parent;
cgrp->root = parent->root;
return cgroup_create(c_parent, dentry, mode | S_IFDIR);
}
-static inline int cgroup_has_css_refs(struct cgroup *cgrp)
+static int cgroup_has_css_refs(struct cgroup *cgrp)
{
/* Check the reference count on each subsystem. Since we
* already established that there are no tasks in the
mutex_unlock(&cgroup_mutex);
return -EBUSY;
}
-
- parent = cgrp->parent;
- root = cgrp->root;
- sb = root->sb;
+ mutex_unlock(&cgroup_mutex);
/*
* Call pre_destroy handlers of subsys. Notify subsystems
*/
cgroup_call_pre_destroy(cgrp);
- if (cgroup_has_css_refs(cgrp)) {
+ mutex_lock(&cgroup_mutex);
+ parent = cgrp->parent;
+ root = cgrp->root;
+ sb = root->sb;
+
+ if (atomic_read(&cgrp->count)
+ || !list_empty(&cgrp->children)
+ || cgroup_has_css_refs(cgrp)) {
mutex_unlock(&cgroup_mutex);
return -EBUSY;
}
list_del(&cgrp->sibling);
spin_lock(&cgrp->dentry->d_lock);
d = dget(cgrp->dentry);
- cgrp->dentry = NULL;
spin_unlock(&d->d_lock);
cgroup_d_remove_dir(d);
int __init cgroup_init_early(void)
{
int i;
- kref_init(&init_css_set.ref);
- kref_get(&init_css_set.ref);
+ atomic_set(&init_css_set.refcount, 1);
INIT_LIST_HEAD(&init_css_set.cg_links);
INIT_LIST_HEAD(&init_css_set.tasks);
INIT_HLIST_NODE(&init_css_set.hlist);
* Called on every change to mm->owner. mm_init_owner() does not
* invoke this routine, since it assigns the mm->owner the first time
* and does not change it.
+ *
+ * The callbacks are invoked with mmap_sem held in read mode.
*/
void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
{
- struct cgroup *oldcgrp, *newcgrp;
+ struct cgroup *oldcgrp, *newcgrp = NULL;
if (need_mm_owner_callback) {
int i;
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
oldcgrp = task_cgroup(old, ss->subsys_id);
- newcgrp = task_cgroup(new, ss->subsys_id);
+ if (new)
+ newcgrp = task_cgroup(new, ss->subsys_id);
if (oldcgrp == newcgrp)
continue;
if (ss->mm_owner_changed)
- ss->mm_owner_changed(ss, oldcgrp, newcgrp);
+ ss->mm_owner_changed(ss, oldcgrp, newcgrp, new);
}
}
}
* cgroup_clone - clone the cgroup the given subsystem is attached to
* @tsk: the task to be moved
* @subsys: the given subsystem
+ * @nodename: the name for the new cgroup
*
* Duplicate the current cgroup in the hierarchy that the given
* subsystem is attached to, and move this task into the new
* child.
*/
-int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys)
+int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
+ char *nodename)
{
struct dentry *dentry;
int ret = 0;
- char nodename[MAX_CGROUP_TYPE_NAMELEN];
struct cgroup *parent, *child;
struct inode *inode;
struct css_set *cg;
cg = tsk->cgroups;
parent = task_cgroup(tsk, subsys->subsys_id);
- snprintf(nodename, MAX_CGROUP_TYPE_NAMELEN, "%d", tsk->pid);
-
/* Pin the hierarchy */
atomic_inc(&parent->root->sb->s_active);
while (!list_empty(&release_list)) {
char *argv[3], *envp[3];
int i;
- char *pathbuf;
+ char *pathbuf = NULL, *agentbuf = NULL;
struct cgroup *cgrp = list_entry(release_list.next,
struct cgroup,
release_list);
list_del_init(&cgrp->release_list);
spin_unlock(&release_list_lock);
pathbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
- if (!pathbuf) {
- spin_lock(&release_list_lock);
- continue;
- }
-
- if (cgroup_path(cgrp, pathbuf, PAGE_SIZE) < 0) {
- kfree(pathbuf);
- spin_lock(&release_list_lock);
- continue;
- }
+ if (!pathbuf)
+ goto continue_free;
+ if (cgroup_path(cgrp, pathbuf, PAGE_SIZE) < 0)
+ goto continue_free;
+ agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
+ if (!agentbuf)
+ goto continue_free;
i = 0;
- argv[i++] = cgrp->root->release_agent_path;
- argv[i++] = (char *)pathbuf;
+ argv[i++] = agentbuf;
+ argv[i++] = pathbuf;
argv[i] = NULL;
i = 0;
* be a slow process */
mutex_unlock(&cgroup_mutex);
call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
- kfree(pathbuf);
mutex_lock(&cgroup_mutex);
+ continue_free:
+ kfree(pathbuf);
+ kfree(agentbuf);
spin_lock(&release_list_lock);
}
spin_unlock(&release_list_lock);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff