Merge tag 'acpi-5.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...

[linux-2.6-microblaze.git] / kernel / pid.c

diff --git a/kernel/pid.c b/kernel/pid.c
index efe87db..2fc0a16 100644 (file)
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -539,6 +539,42 @@ struct pid *pidfd_get_pid(unsigned int fd, unsigned int *flags)
        return pid;
 }
 
+/**
+ * pidfd_get_task() - Get the task associated with a pidfd
+ *
+ * @pidfd: pidfd for which to get the task
+ * @flags: flags associated with this pidfd
+ *
+ * Return the task associated with @pidfd. The function takes a reference on
+ * the returned task. The caller is responsible for releasing that reference.
+ *
+ * Currently, the process identified by @pidfd is always a thread-group leader.
+ * This restriction currently exists for all aspects of pidfds including pidfd
+ * creation (CLONE_PIDFD cannot be used with CLONE_THREAD) and pidfd polling
+ * (only supports thread group leaders).
+ *
+ * Return: On success, the task_struct associated with the pidfd.
+ *        On error, a negative errno number will be returned.
+ */
+struct task_struct *pidfd_get_task(int pidfd, unsigned int *flags)
+{
+       unsigned int f_flags;
+       struct pid *pid;
+       struct task_struct *task;
+
+       pid = pidfd_get_pid(pidfd, &f_flags);
+       if (IS_ERR(pid))
+               return ERR_CAST(pid);
+
+       task = get_pid_task(pid, PIDTYPE_TGID);
+       put_pid(pid);
+       if (!task)
+               return ERR_PTR(-ESRCH);
+
+       *flags = f_flags;
+       return task;
+}
+
 /**
  * pidfd_create() - Create a new pid file descriptor.
  *