sched: add kernel-doc for struct clone_args

Add kernel-doc for struct clone_args for the clone3() syscall.

Link: https://lore.kernel.org/r/20191001114701.24661-3-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

include/uapi/linux/sched.h

@@ -34,8 +34,30 @@
 #define CLONE_IO		0x80000000	/* Clone io context */
 
 #ifndef __ASSEMBLY__
-/*
- * Arguments for the clone3 syscall
+/**
+ * struct clone_args - arguments for the clone3 syscall
+ * @flags:       Flags for the new process as listed above.
+ *               All flags are valid except for CSIGNAL and
+ *               CLONE_DETACHED.
+ * @pidfd:       If CLONE_PIDFD is set, a pidfd will be
+ *               returned in this argument.
+ * @child_tid:   If CLONE_CHILD_SETTID is set, the TID of the
+ *               child process will be returned in the child's
+ *               memory.
+ * @parent_tid:  If CLONE_PARENT_SETTID is set, the TID of
+ *               the child process will be returned in the
+ *               parent's memory.
+ * @exit_signal: The exit_signal the parent process will be
+ *               sent when the child exits.
+ * @stack:       Specify the location of the stack for the
+ *               child process.
+ * @stack_size:  The size of the stack for the child process.
+ * @tls:         If CLONE_SETTLS is set, the tls descriptor
+ *               is set to tls.
+ *
+ * The structure is versioned by size and thus extensible.
+ * New struct members must go at the end of the struct and
+ * must be properly 64bit aligned.
  */
 struct clone_args {
 	__aligned_u64 flags;