Index: kern/kern_descrip.c
===================================================================
RCS file: /usr/ncvs/src/sys/kern/kern_descrip.c,v
retrieving revision 1.294
diff -u -r1.294 kern_descrip.c
--- kern/kern_descrip.c	1 Apr 2006 11:09:54 -0000	1.294
+++ kern/kern_descrip.c	21 Apr 2006 02:19:51 -0000
@@ -359,24 +359,7 @@
 	struct vnode *vp;
 	u_int newmin;
 	int error, flg, tmp;
-	int giant_locked;
-
-	/*
-	 * XXXRW: Some fcntl() calls require Giant -- others don't.  Try to
-	 * avoid grabbing Giant for calls we know don't need it.
-	 */
-	switch (cmd) {
-	case F_DUPFD:
-	case F_GETFD:
-	case F_SETFD:
-	case F_GETFL:
-		giant_locked = 0;
-		break;
-
-	default:
-		giant_locked = 1;
-		mtx_lock(&Giant);
-	}
+	int giant_locked = 0;
 
 	error = 0;
 	flg = F_POSIX;
@@ -391,9 +374,21 @@
 	}
 	pop = &fdp->fd_ofileflags[fd];
 
+	if ((fp->f_ops->fo_flags & DFLAG_MPSAFE) == 0) {
+		switch (cmd) {
+		case F_DUPFD:
+		case F_GETFD:
+		case F_SETFD:
+		case F_GETFL:
+			giant_locked = 0;
+			break;
+		default:
+			giant_locked = 1;
+			mtx_lock(&Giant);
+		}
+	} 
 	switch (cmd) {
 	case F_DUPFD:
-		/* mtx_assert(&Giant, MA_NOTOWNED); */
 		FILEDESC_UNLOCK(fdp);
 		newmin = arg;
 		PROC_LOCK(p);
@@ -408,20 +403,17 @@
 		break;
 
 	case F_GETFD:
-		/* mtx_assert(&Giant, MA_NOTOWNED); */
 		td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0;
 		FILEDESC_UNLOCK(fdp);
 		break;
 
 	case F_SETFD:
-		/* mtx_assert(&Giant, MA_NOTOWNED); */
 		*pop = (*pop &~ UF_EXCLOSE) |
 		    (arg & FD_CLOEXEC ? UF_EXCLOSE : 0);
 		FILEDESC_UNLOCK(fdp);
 		break;
 
 	case F_GETFL:
-		/* mtx_assert(&Giant, MA_NOTOWNED); */
 		FILE_LOCK(fp);
 		td->td_retval[0] = OFLAGS(fp->f_flag);
 		FILE_UNLOCK(fp);
@@ -429,7 +421,6 @@
 		break;
 
 	case F_SETFL:
-		mtx_assert(&Giant, MA_OWNED);
 		FILE_LOCK(fp);
 		fhold_locked(fp);
 		fp->f_flag &= ~FCNTLFLAGS;
@@ -457,7 +448,6 @@
 		break;
 
 	case F_GETOWN:
-		mtx_assert(&Giant, MA_OWNED);
 		fhold(fp);
 		FILEDESC_UNLOCK(fdp);
 		error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td);
@@ -467,7 +457,6 @@
 		break;
 
 	case F_SETOWN:
-		mtx_assert(&Giant, MA_OWNED);
 		fhold(fp);
 		FILEDESC_UNLOCK(fdp);
 		tmp = arg;
@@ -476,12 +465,10 @@
 		break;
 
 	case F_SETLKW:
-		mtx_assert(&Giant, MA_OWNED);
 		flg |= F_WAIT;
 		/* FALLTHROUGH F_SETLK */
 
 	case F_SETLK:
-		mtx_assert(&Giant, MA_OWNED);
 		if (fp->f_type != DTYPE_VNODE) {
 			FILEDESC_UNLOCK(fdp);
 			error = EBADF;
@@ -555,7 +542,6 @@
 		break;
 
 	case F_GETLK:
-		mtx_assert(&Giant, MA_OWNED);
 		if (fp->f_type != DTYPE_VNODE) {
 			FILEDESC_UNLOCK(fdp);
 			error = EBADF;
Index: kern/sys_pipe.c
===================================================================
RCS file: /usr/ncvs/src/sys/kern/sys_pipe.c,v
retrieving revision 1.186
diff -u -r1.186 sys_pipe.c
--- kern/sys_pipe.c	30 Jan 2006 08:25:04 -0000	1.186
+++ kern/sys_pipe.c	15 Apr 2006 20:38:31 -0000
@@ -153,7 +153,7 @@
 	.fo_kqfilter = pipe_kqfilter,
 	.fo_stat = pipe_stat,
 	.fo_close = pipe_close,
-	.fo_flags = DFLAG_PASSABLE
+	.fo_flags = DFLAG_PASSABLE | DFLAG_MPSAFE
 };
 
 static void	filt_pipedetach(struct knote *kn);
Index: kern/sys_socket.c
===================================================================
RCS file: /usr/ncvs/src/sys/kern/sys_socket.c,v
retrieving revision 1.69
diff -u -r1.69 sys_socket.c
--- kern/sys_socket.c	16 Apr 2005 18:46:28 -0000	1.69
+++ kern/sys_socket.c	15 Apr 2006 20:35:06 -0000
@@ -63,7 +63,7 @@
 	.fo_kqfilter = soo_kqfilter,
 	.fo_stat = soo_stat,
 	.fo_close = soo_close,
-	.fo_flags = DFLAG_PASSABLE
+	.fo_flags = DFLAG_PASSABLE | DFLAG_MPSAFE
 };
 
 /* ARGSUSED */
Index: kern/vfs_vnops.c
===================================================================
RCS file: /usr/ncvs/src/sys/kern/vfs_vnops.c,v
retrieving revision 1.241
diff -u -r1.241 vfs_vnops.c
--- kern/vfs_vnops.c	31 Mar 2006 03:54:19 -0000	1.241
+++ kern/vfs_vnops.c	15 Apr 2006 19:31:39 -0000
@@ -78,7 +78,7 @@
 	.fo_kqfilter = vn_kqfilter,
 	.fo_stat = vn_statfile,
 	.fo_close = vn_closefile,
-	.fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
+	.fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE | DFLAG_MPSAFE
 };
 
 int
Index: sys/file.h
===================================================================
RCS file: /usr/ncvs/src/sys/sys/file.h,v
retrieving revision 1.71
diff -u -r1.71 file.h
--- sys/file.h	26 Nov 2005 12:42:35 -0000	1.71
+++ sys/file.h	21 Apr 2006 01:03:11 -0000
@@ -92,6 +92,7 @@
 
 #define DFLAG_PASSABLE	0x01	/* may be passed via unix sockets. */
 #define DFLAG_SEEKABLE	0x02	/* seekable / nonsequential */
+#define DFLAG_MPSAFE	0x04	/* These fileops are MPSAFE */
 
 /*
  * Kernel descriptor table.