- Release Giant a bit earlier on syscall exit.

- Don't try to grab Giant before postsig() in userret() as it is no longer
  needed.
- Don't grab Giant before psignal() in ast() but get the proc lock instead.

5 files changed, 59 insertions, 87 deletions

diff --git a/sys/alpha/alpha/trap.c b/sys/alpha/alpha/trap.c
index 9800090..3f182e5 100644
--- a/sys/alpha/alpha/trap.c
+++ b/sys/alpha/alpha/trap.c
@@ -104,11 +104,9 @@ userret(p, frame, oticks)
 	int sig;
 
 	/* take pending signals */
-	while ((sig = CURSIG(p)) != 0) {
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+	while ((sig = CURSIG(p)) != 0)
 		postsig(sig);
-	}
+
 	mtx_lock_spin(&sched_lock);
 	p->p_pri.pri_level = p->p_pri.pri_user;
 	if (resched_wanted()) {
@@ -126,11 +124,8 @@ userret(p, frame, oticks)
 		mi_switch();
 		mtx_unlock_spin(&sched_lock);
 		PICKUP_GIANT();
-		while ((sig = CURSIG(p)) != 0) {
-			if (!mtx_owned(&Giant))
-				mtx_lock(&Giant);
+		while ((sig = CURSIG(p)) != 0)
 			postsig(sig);
-		}
 		mtx_lock_spin(&sched_lock);
 	} 
 
@@ -729,6 +724,7 @@ syscall(code, framep)
 	if (KTRPOINT(p, KTR_SYSRET))
 		ktrsysret(p->p_tracep, code, error, p->p_retval[0]);
 #endif
+	mtx_unlock(&Giant);
 
 	/*
 	 * This works because errno is findable through the
@@ -736,7 +732,6 @@ syscall(code, framep)
 	 * is not the case, this code will need to be revisited.
 	 */
 	STOPEVENT(p, S_SCX, code);
-	mtx_unlock(&Giant);
 
 #ifdef WITNESS
 	if (witness_list(p)) {
@@ -781,24 +776,24 @@ ast(framep)
 		p->p_sflag &= ~PS_OWEUPC;
 		mtx_unlock_spin(&sched_lock);
 		mtx_lock(&Giant);
-		mtx_lock_spin(&sched_lock);
+		mtx_lock_spin(&sched_lock); /* XXX */
 		addupc_task(p, p->p_stats->p_prof.pr_addr,
 			    p->p_stats->p_prof.pr_ticks);
 	}
 	if (p->p_sflag & PS_ALRMPEND) {
 		p->p_sflag &= ~PS_ALRMPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGVTALRM);
+		PROC_UNLOCK(p);
 		mtx_lock_spin(&sched_lock);
 	}
 	if (p->p_sflag & PS_PROFPEND) {
 		p->p_sflag &= ~PS_PROFPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGPROF);
+		PROC_UNLOCK(p);
 	} else
 		mtx_unlock_spin(&sched_lock);
 
diff --git a/sys/amd64/amd64/trap.c b/sys/amd64/amd64/trap.c
index bb03fa6..7088d0c 100644
--- a/sys/amd64/amd64/trap.c
+++ b/sys/amd64/amd64/trap.c
@@ -172,11 +172,8 @@ userret(p, frame, oticks)
 {
 	int sig;
 
-	while ((sig = CURSIG(p)) != 0) {
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+	while ((sig = CURSIG(p)) != 0)
 		postsig(sig);
-	}
 
 	mtx_lock_spin(&sched_lock);
 	p->p_pri.pri_level = p->p_pri.pri_user;
@@ -195,11 +192,8 @@ userret(p, frame, oticks)
 		mi_switch();
 		mtx_unlock_spin(&sched_lock);
 		PICKUP_GIANT();
-		while ((sig = CURSIG(p)) != 0) {
-			if (!mtx_owned(&Giant))
-				mtx_lock(&Giant);
+		while ((sig = CURSIG(p)) != 0)
 			postsig(sig);
-		}
 		mtx_lock_spin(&sched_lock);
 	}
 
@@ -508,9 +502,9 @@ restart:
 			 */
 			if (frame.tf_eip == (int)cpu_switch_load_gs) {
 				PCPU_GET(curpcb)->pcb_gs = 0;
-				mtx_lock(&Giant);
+				PROC_LOCK(p);
 				psignal(p, SIGBUS);
-				mtx_unlock(&Giant);
+				PROC_UNLOCK(p);
 				goto out;
 			}
 
@@ -1247,18 +1241,18 @@ bad:
 #endif
 
 	/*
+	 * Release Giant if we had to get it
+	 */
+	if (mtx_owned(&Giant))
+		mtx_unlock(&Giant);
+
+	/*
 	 * This works because errno is findable through the
 	 * register set.  If we ever support an emulation where this
 	 * is not the case, this code will need to be revisited.
 	 */
 	STOPEVENT(p, S_SCX, code);
 
-	/*
-	 * Release Giant if we had to get it
-	 */
-	if (mtx_owned(&Giant))
-		mtx_unlock(&Giant);
-
 #ifdef WITNESS
 	if (witness_list(p)) {
 		panic("system call %s returning with mutex(s) held\n",
@@ -1305,17 +1299,17 @@ ast(framep)
 	if (p->p_sflag & PS_ALRMPEND) {
 		p->p_sflag &= ~PS_ALRMPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGVTALRM);
+		PROC_UNLOCK(p);
 		mtx_lock_spin(&sched_lock);
 	}
 	if (p->p_sflag & PS_PROFPEND) {
 		p->p_sflag &= ~PS_PROFPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGPROF);
+		PROC_UNLOCK(p);
 	} else
 		mtx_unlock_spin(&sched_lock);
 
diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c
index bb03fa6..7088d0c 100644
--- a/sys/i386/i386/trap.c
+++ b/sys/i386/i386/trap.c
@@ -172,11 +172,8 @@ userret(p, frame, oticks)
 {
 	int sig;
 
-	while ((sig = CURSIG(p)) != 0) {
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+	while ((sig = CURSIG(p)) != 0)
 		postsig(sig);
-	}
 
 	mtx_lock_spin(&sched_lock);
 	p->p_pri.pri_level = p->p_pri.pri_user;
@@ -195,11 +192,8 @@ userret(p, frame, oticks)
 		mi_switch();
 		mtx_unlock_spin(&sched_lock);
 		PICKUP_GIANT();
-		while ((sig = CURSIG(p)) != 0) {
-			if (!mtx_owned(&Giant))
-				mtx_lock(&Giant);
+		while ((sig = CURSIG(p)) != 0)
 			postsig(sig);
-		}
 		mtx_lock_spin(&sched_lock);
 	}
 
@@ -508,9 +502,9 @@ restart:
 			 */
 			if (frame.tf_eip == (int)cpu_switch_load_gs) {
 				PCPU_GET(curpcb)->pcb_gs = 0;
-				mtx_lock(&Giant);
+				PROC_LOCK(p);
 				psignal(p, SIGBUS);
-				mtx_unlock(&Giant);
+				PROC_UNLOCK(p);
 				goto out;
 			}
 
@@ -1247,18 +1241,18 @@ bad:
 #endif
 
 	/*
+	 * Release Giant if we had to get it
+	 */
+	if (mtx_owned(&Giant))
+		mtx_unlock(&Giant);
+
+	/*
 	 * This works because errno is findable through the
 	 * register set.  If we ever support an emulation where this
 	 * is not the case, this code will need to be revisited.
 	 */
 	STOPEVENT(p, S_SCX, code);
 
-	/*
-	 * Release Giant if we had to get it
-	 */
-	if (mtx_owned(&Giant))
-		mtx_unlock(&Giant);
-
 #ifdef WITNESS
 	if (witness_list(p)) {
 		panic("system call %s returning with mutex(s) held\n",
@@ -1305,17 +1299,17 @@ ast(framep)
 	if (p->p_sflag & PS_ALRMPEND) {
 		p->p_sflag &= ~PS_ALRMPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGVTALRM);
+		PROC_UNLOCK(p);
 		mtx_lock_spin(&sched_lock);
 	}
 	if (p->p_sflag & PS_PROFPEND) {
 		p->p_sflag &= ~PS_PROFPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGPROF);
+		PROC_UNLOCK(p);
 	} else
 		mtx_unlock_spin(&sched_lock);
 
diff --git a/sys/ia64/ia64/trap.c b/sys/ia64/ia64/trap.c
index 1858ded..8486877 100644
--- a/sys/ia64/ia64/trap.c
+++ b/sys/ia64/ia64/trap.c
@@ -85,11 +85,9 @@ userret(register struct proc *p, struct trapframe *frame, u_quad_t oticks)
 	int sig;
 
 	/* take pending signals */
-	while ((sig = CURSIG(p)) != 0) {
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+	while ((sig = CURSIG(p)) != 0)
 		postsig(sig);
-	}
+
 	mtx_lock_spin(&sched_lock);
 	p->p_pri.pri_level = p->p_pri.pri_user;
 	if (resched_wanted()) {
@@ -107,11 +105,8 @@ userret(register struct proc *p, struct trapframe *frame, u_quad_t oticks)
 		mi_switch();
 		mtx_unlock_spin(&sched_lock);
 		PICKUP_GIANT();
-		while ((sig = CURSIG(p)) != 0) {
-			if (!mtx_owned(&Giant))
-				mtx_lock(&Giant);
+		while ((sig = CURSIG(p)) != 0)
 			postsig(sig);
-		}
 		mtx_lock_spin(&sched_lock);
 	}
 
@@ -604,6 +599,7 @@ syscall(int code, u_int64_t *args, struct trapframe *framep)
 	if (KTRPOINT(p, KTR_SYSRET))
 		ktrsysret(p->p_tracep, code, error, p->p_retval[0]);
 #endif
+	mtx_unlock(&Giant);
 
 	/*
 	 * This works because errno is findable through the
@@ -611,7 +607,6 @@ syscall(int code, u_int64_t *args, struct trapframe *framep)
 	 * is not the case, this code will need to be revisited.
 	 */
 	STOPEVENT(p, S_SCX, code);
-	mtx_unlock(&Giant);
 
 #ifdef WITNESS
 	if (witness_list(p)) {
@@ -665,17 +660,17 @@ ast(framep)
 	if (p->p_sflag & PS_ALRMPEND) {
 		p->p_sflag &= ~PS_ALRMPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGVTALRM);
+		PROC_UNLOCK(p);
 		mtx_lock_spin(&sched_lock);
 	}
 	if (p->p_sflag & PS_PROFPEND) {
 		p->p_sflag &= ~PS_PROFPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGPROF);
+		PROC_UNLOCK(p);
 	} else
 		mtx_unlock_spin(&sched_lock);
 
diff --git a/sys/kern/subr_trap.c b/sys/kern/subr_trap.c
index bb03fa6..7088d0c 100644
--- a/sys/kern/subr_trap.c
+++ b/sys/kern/subr_trap.c
@@ -172,11 +172,8 @@ userret(p, frame, oticks)
 {
 	int sig;
 
-	while ((sig = CURSIG(p)) != 0) {
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+	while ((sig = CURSIG(p)) != 0)
 		postsig(sig);
-	}
 
 	mtx_lock_spin(&sched_lock);
 	p->p_pri.pri_level = p->p_pri.pri_user;
@@ -195,11 +192,8 @@ userret(p, frame, oticks)
 		mi_switch();
 		mtx_unlock_spin(&sched_lock);
 		PICKUP_GIANT();
-		while ((sig = CURSIG(p)) != 0) {
-			if (!mtx_owned(&Giant))
-				mtx_lock(&Giant);
+		while ((sig = CURSIG(p)) != 0)
 			postsig(sig);
-		}
 		mtx_lock_spin(&sched_lock);
 	}
 
@@ -508,9 +502,9 @@ restart:
 			 */
 			if (frame.tf_eip == (int)cpu_switch_load_gs) {
 				PCPU_GET(curpcb)->pcb_gs = 0;
-				mtx_lock(&Giant);
+				PROC_LOCK(p);
 				psignal(p, SIGBUS);
-				mtx_unlock(&Giant);
+				PROC_UNLOCK(p);
 				goto out;
 			}
 
@@ -1247,18 +1241,18 @@ bad:
 #endif
 
 	/*
+	 * Release Giant if we had to get it
+	 */
+	if (mtx_owned(&Giant))
+		mtx_unlock(&Giant);
+
+	/*
 	 * This works because errno is findable through the
 	 * register set.  If we ever support an emulation where this
 	 * is not the case, this code will need to be revisited.
 	 */
 	STOPEVENT(p, S_SCX, code);
 
-	/*
-	 * Release Giant if we had to get it
-	 */
-	if (mtx_owned(&Giant))
-		mtx_unlock(&Giant);
-
 #ifdef WITNESS
 	if (witness_list(p)) {
 		panic("system call %s returning with mutex(s) held\n",
@@ -1305,17 +1299,17 @@ ast(framep)
 	if (p->p_sflag & PS_ALRMPEND) {
 		p->p_sflag &= ~PS_ALRMPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGVTALRM);
+		PROC_UNLOCK(p);
 		mtx_lock_spin(&sched_lock);
 	}
 	if (p->p_sflag & PS_PROFPEND) {
 		p->p_sflag &= ~PS_PROFPEND;
 		mtx_unlock_spin(&sched_lock);
-		if (!mtx_owned(&Giant))
-			mtx_lock(&Giant);
+		PROC_LOCK(p);
 		psignal(p, SIGPROF);
+		PROC_UNLOCK(p);
 	} else
 		mtx_unlock_spin(&sched_lock);