Extend struct sysvec with new method sv_schedtail, which is used for an

explicit process at fork trampoline path instead of eventhadler(schedtail)
invocation for each child process.

Remove eventhandler(schedtail) code and change linux ABI to use newly added
sysvec method.

While here replace explicit comparing of module sysentvec structure with the
newly created process sysentvec to detect the linux ABI.

Discussed with:	kib

MFC after:	2 Week

2 files changed, 6 insertions, 3 deletions

diff --git a/sys/compat/linux/linux_emul.c b/sys/compat/linux/linux_emul.c
index 69f1d08..639d403 100644
--- a/sys/compat/linux/linux_emul.c
+++ b/sys/compat/linux/linux_emul.c
@@ -300,13 +300,16 @@ linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
 }
 
 void
-linux_schedtail(void *arg __unused, struct proc *p)
+linux_schedtail(struct thread *td)
 {
 	struct linux_emuldata *em;
+	struct proc *p;
 	int error = 0;
 	int *child_set_tid;
 
-	if (__predict_true(p->p_sysent != &elf_linux_sysvec))
+	p = td->td_proc;
+
+	if (SV_PROC_ABI(p) != SV_ABI_LINUX)
 		return;
 
 	/* find the emuldata */
diff --git a/sys/compat/linux/linux_emul.h b/sys/compat/linux/linux_emul.h
index d517bfd..3acde64 100644
--- a/sys/compat/linux/linux_emul.h
+++ b/sys/compat/linux/linux_emul.h
@@ -82,7 +82,7 @@ struct linux_emuldata	*em_find(struct proc *, int locked);
 
 int	linux_proc_init(struct thread *, pid_t, int);
 void	linux_proc_exit(void *, struct proc *);
-void	linux_schedtail(void *, struct proc *);
+void	linux_schedtail(struct thread *);
 void	linux_proc_exec(void *, struct proc *, struct image_params *);
 void	linux_kill_threads(struct thread *, int);