-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)
-{
- enum cgroup_filetype type = cft->private;
- char *buffer;
- int retval = 0;
-
- if (nbytes >= PATH_MAX)
- return -E2BIG;
-
- /* +1 for nul-terminator */
- buffer = kmalloc(nbytes + 1, GFP_KERNEL);
- if (buffer == NULL)
- return -ENOMEM;
-
- if (copy_from_user(buffer, userbuf, nbytes)) {
- retval = -EFAULT;
- goto out1;
- }
- 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)
- retval = nbytes;
-out2:
- mutex_unlock(&cgroup_mutex);
-out1:
- kfree(buffer);
- return retval;
-}
-