fork: remove do_fork()

Now that all architectures have been switched to use _do_fork() and the new
struct kernel_clone_args calling convention we can remove the legacy
do_fork() helper completely. The calling convention used to be brittle and
do_fork() didn't buy us anything. The only calling convention accepted
should be based on struct kernel_clone_args going forward. It's cleaner and
uniform.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index ddce0ea..9f03c44 100644 (file)
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -96,7 +96,6 @@ extern void exit_files(struct task_struct *);
 extern void exit_itimers(struct signal_struct *);
 
 extern long _do_fork(struct kernel_clone_args *kargs);
-extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
 struct task_struct *fork_idle(int);
 struct mm_struct *copy_init_mm(void);
 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);

diff --git a/kernel/fork.c b/kernel/fork.c
index 9875aeb..0fd7eb1 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2493,29 +2493,6 @@ long _do_fork(struct kernel_clone_args *args)
        return nr;
 }
 
-#ifndef CONFIG_HAVE_COPY_THREAD_TLS
-/* For compatibility with architectures that call do_fork directly rather than
- * using the syscall entry points below. */
-long do_fork(unsigned long clone_flags,
-             unsigned long stack_start,
-             unsigned long stack_size,
-             int __user *parent_tidptr,
-             int __user *child_tidptr)
-{
-       struct kernel_clone_args args = {
-               .flags          = (lower_32_bits(clone_flags) & ~CSIGNAL),
-               .pidfd          = parent_tidptr,
-               .child_tid      = child_tidptr,
-               .parent_tid     = parent_tidptr,
-               .exit_signal    = (lower_32_bits(clone_flags) & CSIGNAL),
-               .stack          = stack_start,
-               .stack_size     = stack_size,
-       };
-
-       return _do_fork(&args);
-}
-#endif
-
 /*
  * Create a kernel thread.
  */
@@ -2923,7 +2900,7 @@ static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp
 /*
  * unshare allows a process to 'unshare' part of the process
  * context which was originally shared using clone.  copy_*
- * functions used by do_fork() cannot be used here directly
+ * functions used by _do_fork() cannot be used here directly
  * because they modify an inactive task_struct that is being
  * constructed. Here we are modifying the current, active,
  * task_struct.