From 24d19117052f25120edb3b4a06c338a1458ca008 Mon Sep 17 00:00:00 2001
From: trasz <trasz@FreeBSD.org>
Date: Wed, 28 Oct 2020 14:43:38 +0000
Subject: [PATCH] Add local variable to store the sysent pointer.  Just a
 cleanup, no functional changes.

Reviewed by:	kib (earlier version)
MFC after:	2 weeks
Sponsored by:	EPSRC
Differential Revision:	https://reviews.freebsd.org/D26977
---
 sys/kern/subr_syscall.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/sys/kern/subr_syscall.c b/sys/kern/subr_syscall.c
index 381756b37323..bc5dafaf921c 100644
--- a/sys/kern/subr_syscall.c
+++ b/sys/kern/subr_syscall.c
@@ -59,6 +59,7 @@ syscallenter(struct thread *td)
 {
 	struct proc *p;
 	struct syscall_args *sa;
+	struct sysent *se;
 	int error, traced;
 
 	VM_CNT_INC(v_syscall);
@@ -77,9 +78,10 @@ syscallenter(struct thread *td)
 		PROC_UNLOCK(p);
 	}
 	error = (p->p_sysent->sv_fetch_syscall_args)(td);
+	se = sa->callp;
 #ifdef KTRACE
 	if (KTRPOINT(td, KTR_SYSCALL))
-		ktrsyscall(sa->code, sa->callp->sy_narg, sa->args);
+		ktrsyscall(sa->code, se->sy_narg, sa->args);
 #endif
 	KTR_START4(KTR_SYSC, "syscall", syscallname(p, sa->code),
 	    (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "arg0:%p", sa->args[0],
@@ -102,9 +104,10 @@ syscallenter(struct thread *td)
 		 * modified registers or memory.
 		 */
 		error = (p->p_sysent->sv_fetch_syscall_args)(td);
+		se = sa->callp;
 #ifdef KTRACE
 		if (KTRPOINT(td, KTR_SYSCALL))
-			ktrsyscall(sa->code, sa->callp->sy_narg, sa->args);
+			ktrsyscall(sa->code, se->sy_narg, sa->args);
 #endif
 		if (error != 0) {
 			td->td_errno = error;
@@ -118,13 +121,13 @@ syscallenter(struct thread *td)
 	 * flagged with SYF_CAPENABLED.
 	 */
 	if (__predict_false(IN_CAPABILITY_MODE(td) &&
-	    !(sa->callp->sy_flags & SYF_CAPENABLED))) {
+	    (se->sy_flags & SYF_CAPENABLED) == 0)) {
 		td->td_errno = error = ECAPMODE;
 		goto retval;
 	}
 #endif
 
-	error = syscall_thread_enter(td, sa->callp);
+	error = syscall_thread_enter(td, se);
 	if (error != 0) {
 		td->td_errno = error;
 		goto retval;
@@ -145,10 +148,10 @@ syscallenter(struct thread *td)
 	    AUDIT_SYSCALL_ENTER(sa->code, td))) {
 #ifdef KDTRACE_HOOKS
 		/* Give the syscall:::entry DTrace probe a chance to fire. */
-		if (__predict_false(sa->callp->sy_entry != 0))
+		if (__predict_false(se->sy_entry != 0))
 			(*systrace_probe_func)(sa, SYSTRACE_ENTRY, 0);
 #endif
-		error = (sa->callp->sy_call)(td, sa->args);
+		error = (se->sy_call)(td, sa->args);
 		/* Save the latest error return value. */
 		if (__predict_false((td->td_pflags & TDP_NERRNO) != 0))
 			td->td_pflags &= ~TDP_NERRNO;
@@ -168,19 +171,19 @@ syscallenter(struct thread *td)
 
 #ifdef KDTRACE_HOOKS
 		/* Give the syscall:::return DTrace probe a chance to fire. */
-		if (__predict_false(sa->callp->sy_return != 0))
+		if (__predict_false(se->sy_return != 0))
 			(*systrace_probe_func)(sa, SYSTRACE_RETURN,
 			    error ? -1 : td->td_retval[0]);
 #endif
 	} else {
-		error = (sa->callp->sy_call)(td, sa->args);
+		error = (se->sy_call)(td, sa->args);
 		/* Save the latest error return value. */
 		if (__predict_false((td->td_pflags & TDP_NERRNO) != 0))
 			td->td_pflags &= ~TDP_NERRNO;
 		else
 			td->td_errno = error;
 	}
-	syscall_thread_exit(td, sa->callp);
+	syscall_thread_exit(td, se);
 
  retval:
 	KTR_STOP4(KTR_SYSC, "syscall", syscallname(p, sa->code),