From 6809658d1c9ca4eeca1cc691f6104b6ac431e296 Mon Sep 17 00:00:00 2001
From: phk <phk@FreeBSD.org>
Date: Mon, 15 Nov 2004 08:47:18 +0000
Subject: Add pbgetbo()/pbrelbo() lighter weight versions of
 pbgetvp()/pbrelvp().

---
 sys/sys/buf.h     |  2 ++
 sys/vm/vm_pager.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

(limited to 'sys')

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;
+}
-- 
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