All call sites of sys_wait4() set *rusage to NULL. Therefore, there is no need for the copy_to_user() handling of *rusage, and we can use kernel_wait4() directly.
This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.ga17...@light.dominikbrodowski.net Cc: Luis R. Rodriguez <mcg...@kernel.org> Cc: Al Viro <v...@zeniv.linux.org.uk> Cc: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Dominik Brodowski <li...@dominikbrodowski.net> --- kernel/exit.c | 2 +- kernel/pid_namespace.c | 6 +++--- kernel/umh.c | 4 ++-- 3 files changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/exit.c b/kernel/exit.c index 995453d9fb55..c3c7ac560114 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1691,7 +1691,7 @@ SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr, */ SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options) { - return sys_wait4(pid, stat_addr, options, NULL); + return kernel_wait4(pid, stat_addr, options, NULL); } #endif diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index 0b53eef7d34b..93b57f026688 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -242,16 +242,16 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns) /* * Reap the EXIT_ZOMBIE children we had before we ignored SIGCHLD. - * sys_wait4() will also block until our children traced from the + * kernel_wait4() will also block until our children traced from the * parent namespace are detached and become EXIT_DEAD. */ do { clear_thread_flag(TIF_SIGPENDING); - rc = sys_wait4(-1, NULL, __WALL, NULL); + rc = kernel_wait4(-1, NULL, __WALL, NULL); } while (rc != -ECHILD); /* - * sys_wait4() above can't reap the EXIT_DEAD children but we do not + * kernel_wait4() above can't reap the EXIT_DEAD children but we do not * really care, we could reparent them to the global init. We could * exit and reap ->child_reaper even if it is not the last thread in * this pid_ns, free_pid(pid_allocated == 0) calls proc_cleanup_work(), diff --git a/kernel/umh.c b/kernel/umh.c index 18e5fa4b0e71..f76b3ff876cf 100644 --- a/kernel/umh.c +++ b/kernel/umh.c @@ -118,7 +118,7 @@ static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) { pid_t pid; - /* If SIGCLD is ignored sys_wait4 won't populate the status. */ + /* If SIGCLD is ignored kernel_wait4 won't populate the status. */ kernel_sigaction(SIGCHLD, SIG_DFL); pid = kernel_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD); if (pid < 0) { @@ -135,7 +135,7 @@ static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) * * Thus the __user pointer cast is valid here. */ - sys_wait4(pid, (int __user *)&ret, 0, NULL); + kernel_wait4(pid, (int __user *)&ret, 0, NULL); /* * If ret is 0, either call_usermodehelper_exec_async failed and -- 2.16.3
