Increase size of the clone bitmap (revised diff after revert). I have

tested this with fuse _and_ drm on amd64 and macppc. Also tested with
cloning bpf (not in the tree) on macppc.

ok mikeb
"looks correct to me" millert

The original commit message is as follows:

Increase size of the clone bitmap. A limit of only 64 device clones
turned out to be too low for the upcoming work on cloning bpf. The new
limit is 1024 device clones. As part of the size increase, the bitmap
has been changed to be allocated separately to avoid bloating all device
nodes, as suggested by guenther, millert and deraadt.

ok millert mikeb

2 files changed, 16 insertions, 5 deletions

diff --git a/sys/kern/spec_vnops.c b/sys/kern/spec_vnops.c
index c8754e7a80b..b2e104fc28e 100644
--- a/sys/kern/spec_vnops.c
+++ b/sys/kern/spec_vnops.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: spec_vnops.c,v 1.88 2016/04/01 11:51:55 mikeb Exp $	*/
+/*	$OpenBSD: spec_vnops.c,v 1.89 2016/04/05 19:26:15 natano Exp $	*/
 /*	$NetBSD: spec_vnops.c,v 1.29 1996/04/22 01:42:38 christos Exp $	*/
 
 /*
@@ -707,13 +707,13 @@ spec_open_clone(struct vop_open_args *ap)
 	if (minor(vp->v_rdev) >= (1 << CLONE_SHIFT))
 		return (ENXIO);
 
-	for (i = 1; i < sizeof(vp->v_specbitmap) * NBBY; i++)
+	for (i = 1; i < CLONE_MAPSZ * NBBY; i++)
 		if (isclr(vp->v_specbitmap, i)) {
 			setbit(vp->v_specbitmap, i);
 			break;
 		}
 
-	if (i == sizeof(vp->v_specbitmap) * NBBY)
+	if (i == CLONE_MAPSZ * NBBY)
 		return (EBUSY); /* too many open instances */
 
 	error = cdevvp(makedev(major(vp->v_rdev),
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 629429b7e72..38b0f520572 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vfs_subr.c,v 1.242 2016/04/01 11:51:55 mikeb Exp $	*/
+/*	$OpenBSD: vfs_subr.c,v 1.243 2016/04/05 19:26:15 natano Exp $	*/
 /*	$NetBSD: vfs_subr.c,v 1.53 1996/04/22 01:39:13 christos Exp $	*/
 
 /*
@@ -555,7 +555,13 @@ loop:
 		nvp->v_specnext = *vpp;
 		nvp->v_specmountpoint = NULL;
 		nvp->v_speclockf = NULL;
-		memset(nvp->v_specbitmap, 0, sizeof(nvp->v_specbitmap));
+		nvp->v_specbitmap = NULL;
+		if (nvp->v_type == VCHR &&
+		    (cdevsw[major(nvp_rdev)].d_flags & D_CLONE) &&
+		    (minor(nvp_rdev) >> CLONE_SHIFT == 0)) {
+			nvp->v_specbitmap = malloc(CLONE_MAPSZ, M_VNODE,
+			    M_WAITOK | M_ZERO);
+		}
 		*vpp = nvp;
 		if (vp != NULLVP) {
 			nvp->v_flag |= VALIASED;
@@ -1093,6 +1099,11 @@ vgonel(struct vnode *vp, struct proc *p)
 				vx->v_flag &= ~VALIASED;
 			vp->v_flag &= ~VALIASED;
 		}
+		if (vp->v_type == VCHR &&
+		    (cdevsw[major(vp->v_rdev)].d_flags & D_CLONE) &&
+		    (minor(vp->v_rdev) >> CLONE_SHIFT == 0)) {
+			free(vp->v_specbitmap, M_VNODE, CLONE_MAPSZ);
+		}
 		free(vp->v_specinfo, M_VNODE, sizeof(struct specinfo));
 		vp->v_specinfo = NULL;
 	}