- Introduce the function lockmgr_recursed() which returns true if the

  lockmgr lkp, when held in exclusive mode, is recursed
- Introduce the function BUF_RECURSED() which does the same for bufobj
  locks based on the top of lockmgr_recursed()
- Introduce the function BUF_ISLOCKED() which works like the counterpart
  VOP_ISLOCKED(9), showing the state of lockmgr linked with the bufobj

BUF_RECURSED() and BUF_ISLOCKED() entirely replace the usage of bogus
BUF_REFCNT() in a more explicative and SMP-compliant way.
This allows us to axe out BUF_REFCNT() and leaving the function
lockcount() totally unused in our stock kernel. Further commits will
axe lockcount() as well as part of lockmgr() cleanup.

KPI results, obviously, broken so further commits will update manpages
and freebsd version.

Tested by: kris (on UFS and NFS)

2 files changed, 4 insertions, 5 deletions

diff --git a/sys/gnu/fs/xfs/FreeBSD/xfs_buf.c b/sys/gnu/fs/xfs/FreeBSD/xfs_buf.c
index 30aafc4..65030df 100644
--- a/sys/gnu/fs/xfs/FreeBSD/xfs_buf.c
+++ b/sys/gnu/fs/xfs/FreeBSD/xfs_buf.c
@@ -86,7 +86,7 @@ xfs_buf_get_empty(size_t size,  xfs_buftarg_t *target)
 		bp->b_bufsize = size;
 		bp->b_bcount = size;
 
-		KASSERT(BUF_REFCNT(bp) == 1,
+		KASSERT(BUF_ISLOCKED(bp),
 			("xfs_buf_get_empty: bp %p not locked",bp));
 
 		xfs_buf_set_target(bp, target);
@@ -103,7 +103,7 @@ xfs_buf_get_noaddr(size_t len, xfs_buftarg_t *target)
 
 	bp = geteblk(len);
 	if (bp != NULL) {
-		KASSERT(BUF_REFCNT(bp) == 1,
+		KASSERT(BUF_ISLOCKED(bp),
 			("xfs_buf_get_empty: bp %p not locked",bp));
 
 		xfs_buf_set_target(bp, target);
@@ -163,7 +163,7 @@ XFS_bwrite(xfs_buf_t *bp)
 		if ((bp->b_flags & B_ASYNC) == 0) {
 			error = bufwait(bp);
 #if 0
-			if (BUF_REFCNT(bp) > 1)
+			if (BUF_LOCKRECURSED(bp))
 				BUF_UNLOCK(bp);
 			else
 				brelse(bp);
diff --git a/sys/gnu/fs/xfs/FreeBSD/xfs_buf.h b/sys/gnu/fs/xfs/FreeBSD/xfs_buf.h
index c27a14c..34e579d 100644
--- a/sys/gnu/fs/xfs/FreeBSD/xfs_buf.h
+++ b/sys/gnu/fs/xfs/FreeBSD/xfs_buf.h
@@ -160,7 +160,6 @@ xfs_buf_get_error(struct buf *bp)
 
 #define XFS_BUF_HOLD(x)		((void)0)
 #define XFS_BUF_UNHOLD(x)	((void)0)
-#define XFS_BUF_ISHOLD(x)	BUF_REFCNT(x)
 
 #define XFS_BUF_READ(x)		((x)->b_iocmd = BIO_READ)
 #define XFS_BUF_UNREAD(x)	((x)->b_iocmd = 0)
@@ -234,7 +233,7 @@ xfs_buf_offset(xfs_buf_t *bp, size_t offset)
 #define	XFS_BUF_SET_VTYPE(bp, type)
 #define	XFS_BUF_SET_REF(bp, ref)
 
-#define	XFS_BUF_VALUSEMA(bp)	(BUF_REFCNT(bp)? 0 : 1)
+#define	XFS_BUF_VALUSEMA(bp)	(BUF_ISLOCKED(bp) ? 0 : 1)
 #define	XFS_BUF_CPSEMA(bp) \
 	(BUF_LOCK(bp, LK_EXCLUSIVE|LK_CANRECURSE | LK_SLEEPFAIL, NULL) == 0)