Add pbgetbo()/pbrelbo() lighter weight versions of pbgetvp()/pbrelvp().

2 files changed, 44 insertions, 0 deletions

diff --git a/sys/sys/buf.h b/sys/sys/buf.h
index bd12ca7..5a1cea4 100644
--- a/sys/sys/buf.h
+++ b/sys/sys/buf.h
@@ -519,7 +519,9 @@ void	vunmapbuf(struct buf *);
 void	relpbuf(struct buf *, int *);
 void	brelvp(struct buf *);
 void	bgetvp(struct vnode *, struct buf *);
+void	pbgetbo(struct bufobj *bo, struct buf *bp);
 void	pbgetvp(struct vnode *, struct buf *);
+void	pbrelbo(struct buf *);
 void	pbrelvp(struct buf *);
 int	allocbuf(struct buf *bp, int size);
 void	reassignbuf(struct buf *);
diff --git a/sys/vm/vm_pager.c b/sys/vm/vm_pager.c
index a8d061a..87f74d8 100644
--- a/sys/vm/vm_pager.c
+++ b/sys/vm/vm_pager.c
@@ -442,6 +442,24 @@ pbgetvp(struct vnode *vp, struct buf *bp)
 }
 
 /*
+ * Associate a p-buffer with a vnode.
+ *
+ * Also sets B_PAGING flag to indicate that vnode is not fully associated
+ * with the buffer.  i.e. the bp has not been linked into the vnode or
+ * ref-counted.
+ */
+void
+pbgetbo(struct bufobj *bo, struct buf *bp)
+{
+
+	KASSERT(bp->b_vp == NULL, ("pbgetbo: not free (vnode)"));
+	KASSERT(bp->b_bufobj == NULL, ("pbgetbo: not free (bufobj)"));
+
+	bp->b_flags |= B_PAGING;
+	bp->b_bufobj = bo;
+}
+
+/*
  * Disassociate a p-buffer from a vnode.
  */
 void
@@ -465,3 +483,27 @@ pbrelvp(struct buf *bp)
 	bp->b_bufobj = NULL;
 	bp->b_flags &= ~B_PAGING;
 }
+
+/*
+ * Disassociate a p-buffer from a bufobj.
+ */
+void
+pbrelbo(struct buf *bp)
+{
+
+	KASSERT(bp->b_vp == NULL, ("pbrelbo: vnode"));
+	KASSERT(bp->b_bufobj != NULL, ("pbrelbo: NULL bufobj"));
+
+	/* XXX REMOVE ME */
+	BO_LOCK(bp->b_bufobj);
+	if (TAILQ_NEXT(bp, b_bobufs) != NULL) {
+		panic(
+		    "relpbuf(): b_vp was probably reassignbuf()d %p %x",
+		    bp,
+		    (int)bp->b_flags
+		);
+	}
+	BO_UNLOCK(bp->b_bufobj);
+	bp->b_bufobj = NULL;
+	bp->b_flags &= ~B_PAGING;
+}