From 1e3e78d23986d70575fb080f920c8bf5e0fd90f7 Mon Sep 17 00:00:00 2001
From: Marcel Moolenaar <marcel@FreeBSD.org>
Date: Thu, 8 Jul 2004 21:08:07 +0000
Subject: [PATCH] MFamd64 (1.275): Reduce the scope of the Giant lock being
 held for non-mpsafe syscalls. There was way too much code being covered.

---
 sys/ia64/ia64/trap.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/sys/ia64/ia64/trap.c b/sys/ia64/ia64/trap.c
index 5b0049417ac3..0145ed2b0a6c 100644
--- a/sys/ia64/ia64/trap.c
+++ b/sys/ia64/ia64/trap.c
@@ -973,11 +973,6 @@ syscall(struct trapframe *tf)
   	else
  		callp = &p->p_sysent->sv_table[code];
 
-	/*
-	 * Try to run the syscall without Giant if the syscall is MP safe.
-	 */
-	if ((callp->sy_narg & SYF_MPSAFE) == 0)
-		mtx_lock(&Giant);
 #ifdef KTRACE
 	if (KTRPOINT(td, KTR_SYSCALL))
 		ktrsyscall(code, (callp->sy_narg & SYF_ARGMASK), args);
@@ -991,7 +986,15 @@ syscall(struct trapframe *tf)
 
 	PTRACESTOP_SC(p, td, S_PT_SCE);
 
-	error = (*callp->sy_call)(td, args);
+	/*
+	 * Grab Giant if the syscall is not flagged as MP safe.
+	 */
+	if ((callp->sy_narg & SYF_MPSAFE) == 0) {
+		mtx_lock(&Giant);
+		error = (*callp->sy_call)(td, args);
+		mtx_unlock(&Giant);
+	} else
+		error = (*callp->sy_call)(td, args);
 
 	if (error != EJUSTRETURN) {
 		/*
@@ -1013,12 +1016,6 @@ syscall(struct trapframe *tf)
 		}
 	}
 
-	/*
-	 * Release Giant if we had to get it.
-	 */
-	if ((callp->sy_narg & SYF_MPSAFE) == 0)
-		mtx_unlock(&Giant);
-
 	userret(td, tf, sticks);
 
 #ifdef KTRACE