Do not relock fdp in fdrelease(). This prevents unnecessary locking

in the common case.

OK mpi@

4 files changed, 28 insertions, 18 deletions

diff --git a/sys/kern/exec_script.c b/sys/kern/exec_script.c
index 788260254f5..a31fa5a3269 100644
--- a/sys/kern/exec_script.c
+++ b/sys/kern/exec_script.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: exec_script.c,v 1.47 2018/06/18 09:15:05 mpi Exp $	*/
+/*	$OpenBSD: exec_script.c,v 1.48 2019/07/15 04:11:03 visa Exp $	*/
 /*	$NetBSD: exec_script.c,v 1.13 1996/02/04 02:15:06 christos Exp $	*/
 
 /*
@@ -260,8 +260,8 @@ fail:
 	if (epp->ep_flags & EXEC_HASFD) {
 		epp->ep_flags &= ~EXEC_HASFD;
 		fdplock(p->p_fd);
+		/* fdrelease() unlocks p->p_fd. */
 		(void) fdrelease(p, epp->ep_fd);
-		fdpunlock(p->p_fd);
 	} else
 		vn_close(scriptvp, FREAD, p->p_ucred, p);
 
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index c38ee669517..7370a56b74a 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_descrip.c,v 1.190 2019/07/12 13:56:27 solene Exp $	*/
+/*	$OpenBSD: kern_descrip.c,v 1.191 2019/07/15 04:11:03 visa Exp $	*/
 /*	$NetBSD: kern_descrip.c,v 1.42 1996/03/30 22:24:38 christos Exp $	*/
 
 /*
@@ -741,8 +741,10 @@ fdrelease(struct proc *p, int fd)
 	fdpassertlocked(fdp);
 
 	fp = fd_getfile(fdp, fd);
-	if (fp == NULL)
+	if (fp == NULL) {
+		fdpunlock(fdp);
 		return (EBADF);
+	}
 	/* Prevent race with kevent. */
 	KERNEL_LOCK();
 	fdremove(fdp, fd);
@@ -750,8 +752,7 @@ fdrelease(struct proc *p, int fd)
 	fdpunlock(fdp);
 	error = closef(fp, p);
 	KERNEL_UNLOCK();
-	fdplock(fdp);
-	return error;
+	return (error);
 }
 
 /*
@@ -767,8 +768,8 @@ sys_close(struct proc *p, void *v, register_t *retval)
 	struct filedesc *fdp = p->p_fd;
 
 	fdplock(fdp);
+	/* fdrelease unlocks fdp. */
 	error = fdrelease(p, fd);
-	fdpunlock(fdp);
 
 	return (error);
 }
@@ -1426,8 +1427,11 @@ fdcloseexec(struct proc *p)
 	fdplock(fdp);
 	for (fd = 0; fd <= fdp->fd_lastfile; fd++) {
 		fdp->fd_ofileflags[fd] &= ~UF_PLEDGED;
-		if (fdp->fd_ofileflags[fd] & UF_EXCLOSE)
+		if (fdp->fd_ofileflags[fd] & UF_EXCLOSE) {
+			/* fdrelease() unlocks fdp. */
 			(void) fdrelease(p, fd);
+			fdplock(fdp);
+		}
 	}
 	fdpunlock(fdp);
 }
@@ -1447,8 +1451,11 @@ sys_closefrom(struct proc *p, void *v, register_t *retval)
 		return (EBADF);
 	}
 
-	for (i = startfd; i <= fdp->fd_lastfile; i++)
+	for (i = startfd; i <= fdp->fd_lastfile; i++) {
+		/* fdrelease() unlocks fdp. */
 		fdrelease(p, i);
+		fdplock(fdp);
+	}
 
 	fdpunlock(fdp);
 	return (0);
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 301d847f1c8..dedbe6fc73d 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_exec.c,v 1.206 2019/06/21 09:39:48 visa Exp $	*/
+/*	$OpenBSD: kern_exec.c,v 1.207 2019/07/15 04:11:03 visa Exp $	*/
 /*	$NetBSD: kern_exec.c,v 1.75 1996/02/09 18:59:28 christos Exp $	*/
 
 /*-
@@ -724,8 +724,8 @@ bad:
 	if (pack.ep_flags & EXEC_HASFD) {
 		pack.ep_flags &= ~EXEC_HASFD;
 		fdplock(p->p_fd);
+		/* fdrelease unlocks p->p_fd. */
 		(void) fdrelease(p, pack.ep_fd);
-		fdpunlock(p->p_fd);
 	}
 	if (pack.ep_interp != NULL)
 		pool_put(&namei_pool, pack.ep_interp);
diff --git a/sys/kern/sys_pipe.c b/sys/kern/sys_pipe.c
index 9fecf1b6df6..91df07fdcaf 100644
--- a/sys/kern/sys_pipe.c
+++ b/sys/kern/sys_pipe.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sys_pipe.c,v 1.92 2019/07/14 10:21:11 semarie Exp $	*/
+/*	$OpenBSD: sys_pipe.c,v 1.93 2019/07/15 04:11:03 visa Exp $	*/
 
 /*
  * Copyright (c) 1996 John S. Dyson
@@ -177,15 +177,18 @@ dopipe(struct proc *p, int *ufds, int flags)
 	fdinsert(fdp, fds[1], cloexec, wf);
 
 	error = copyout(fds, ufds, sizeof(fds));
-	if (error != 0) {
+	if (error == 0) {
+		fdpunlock(fdp);
+#ifdef KTRACE
+		if (KTRPOINT(p, KTR_STRUCT))
+			ktrfds(p, fds, 2);
+#endif
+	} else {
+		/* fdrelease() unlocks fdp. */
 		fdrelease(p, fds[0]);
+		fdplock(fdp);
 		fdrelease(p, fds[1]);
 	}
-#ifdef KTRACE
-	else if (KTRPOINT(p, KTR_STRUCT))
-		ktrfds(p, fds, 2);
-#endif
-	fdpunlock(fdp);
 
 	FRELE(rf, p);
 	FRELE(wf, p);