MFi386: merge changes from i386/trap.c rev 1.212

If the credential on an incoming thread is correct, don't bother
reaquiring it. In the same vein, don't bother dropping the thread cred
when going to userland. We are guaranteed to need it when we come back,
(which we are guaranteed to do).

1 files changed, 8 insertions, 6 deletions

diff --git a/sys/alpha/alpha/trap.c b/sys/alpha/alpha/trap.c
index c4c402a..2cdf540d 100644
--- a/sys/alpha/alpha/trap.c
+++ b/sys/alpha/alpha/trap.c
@@ -298,9 +298,8 @@ trap(a0, a1, a2, entry, framep)
 		sticks = td->td_kse->ke_sticks;
 		td->td_frame = framep;
 		KASSERT(td->td_ucred == NULL, ("already have a ucred"));
-		PROC_LOCK(p);
-		td->td_ucred = crhold(p->p_ucred);
-		PROC_UNLOCK(p);
+		if (td->td_ucred != p->p_ucred)
+			cred_update_thread(td);
 	} else {
 		sticks = 0;		/* XXX bogus -Wuninitialized warning */
 		KASSERT(cold || td->td_ucred != NULL,
@@ -626,10 +625,12 @@ out:
 		framep->tf_regs[FRAME_SP] = alpha_pal_rdusp();
 		userret(td, framep, sticks);
 		mtx_assert(&Giant, MA_NOTOWNED);
+#ifdef	INVARIANTS
 		mtx_lock(&Giant);
 		crfree(td->td_ucred);
 		mtx_unlock(&Giant);
 		td->td_ucred = NULL;
+#endif
 	}
 	return;
 
@@ -699,9 +700,8 @@ syscall(code, framep)
 	opc = framep->tf_regs[FRAME_PC] - 4;
 	sticks = td->td_kse->ke_sticks;
 	KASSERT(td->td_ucred == NULL, ("already have a ucred"));
-	PROC_LOCK(p);
-	td->td_ucred = crhold(p->p_ucred);
-	PROC_UNLOCK(p);
+	if (td->td_ucred != p->p_ucred)
+		cred_update_thread(td);
 
 #ifdef DIAGNOSTIC
 	alpha_fpstate_check(td);
@@ -822,10 +822,12 @@ syscall(code, framep)
 	 */
 	STOPEVENT(p, S_SCX, code);
 
+#ifdef	INVARIANTS
 	mtx_lock(&Giant);
 	crfree(td->td_ucred);
 	mtx_unlock(&Giant);
 	td->td_ucred = NULL;
+#endif
 #ifdef WITNESS
 	if (witness_list(td)) {
 		panic("system call %s returning with mutex(s) held\n",