Unverified Commit ff2a9112 authored by Christian Brauner's avatar Christian Brauner
Browse files

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: default avatarChristian Brauner <christian.brauner@ubuntu.com>
parent adc7092e

include/linux/sched/task.h

+0 −1
Original line number Diff line number Diff line
@@ -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);

kernel/fork.c

+1 −24
Original line number Diff line number Diff line
@@ -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.

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