The old _do_fork() helper doesn't follow naming conventions of in-kernel helpers for syscalls. The process creation cleanup in [1] didn't change the name to something more reasonable mainly because _do_fork() was used in quite a few places. So sending this as a separate series seemed the better strategy.
This commit does two things: 1. renames _do_fork() to kernel_clone() but keeps _do_fork() as a simple static inline wrapper around kernel_clone(). 2. Changes the return type from long to pid_t. This aligns kernel_thread() and kernel_clone(). Also, the return value from kernel_clone that is surfaced in fork(), vfork(), clone(), and clone3() is taken from pid_vrn() which returns a pid_t too.
Follow-up patches will switch each caller of _do_fork() and each place where it is referenced over to kernel_clone(). After all these changes are done, we can remove _do_fork() completely and will only be left with kernel_clone().
[1]: 9ba27414f2ec ("Merge tag 'fork-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux") Cc: Thomas Gleixner tglx@linutronix.de Cc: Ingo Molnar mingo@kernel.org Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: "Peter Zijlstra (Intel)" peterz@infradead.org Signed-off-by: Christian Brauner christian.brauner@ubuntu.com --- /* v2 */ - Matthew Wilcox (Oracle) willy@infradead.org: - make kernel_clone() return pid_t --- include/linux/sched/task.h | 6 +++++- kernel/fork.c | 16 ++++++++-------- 2 files changed, 13 insertions(+), 9 deletions(-)
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index a98965007eef..d4428039c3c1 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -83,7 +83,11 @@ extern void do_group_exit(int); extern void exit_files(struct task_struct *); extern void exit_itimers(struct signal_struct *);
-extern long _do_fork(struct kernel_clone_args *kargs); +extern pid_t kernel_clone(struct kernel_clone_args *kargs); +static inline long _do_fork(struct kernel_clone_args *kargs) +{ + return kernel_clone(kargs); +} 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 4d32190861bd..d822c7a4b9c4 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2384,14 +2384,14 @@ struct mm_struct *copy_init_mm(void) * * args->exit_signal is expected to be checked for sanity by the caller. */ -long _do_fork(struct kernel_clone_args *args) +pid_t kernel_clone(struct kernel_clone_args *args) { u64 clone_flags = args->flags; struct completion vfork; struct pid *pid; struct task_struct *p; int trace = 0; - long nr; + pid_t nr;
/* * For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument @@ -2477,7 +2477,7 @@ pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) .stack_size = (unsigned long)arg, };
- return _do_fork(&args); + return kernel_clone(&args); }
#ifdef __ARCH_WANT_SYS_FORK @@ -2488,7 +2488,7 @@ SYSCALL_DEFINE0(fork) .exit_signal = SIGCHLD, };
- return _do_fork(&args); + return kernel_clone(&args); #else /* can not support in nommu mode */ return -EINVAL; @@ -2504,7 +2504,7 @@ SYSCALL_DEFINE0(vfork) .exit_signal = SIGCHLD, };
- return _do_fork(&args); + return kernel_clone(&args); } #endif
@@ -2542,7 +2542,7 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, .tls = tls, };
- return _do_fork(&args); + return kernel_clone(&args); } #endif
@@ -2700,7 +2700,7 @@ SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size) if (!clone3_args_valid(&kargs)) return -EINVAL;
- return _do_fork(&kargs); + return kernel_clone(&kargs); } #endif
@@ -2863,7 +2863,7 @@ int unshare_fd(unsigned long unshare_flags, unsigned int max_fds, /* * 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 kernel_clone() 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.