Switch mfs to bufq. This simplifies the code, gives us queue limits for

free and uses FIFO queueing (rather than the current LIFO queueing).

Tested by sthen@

ok beck@ krw@

3 files changed, 33 insertions, 54 deletions

diff --git a/sys/ufs/mfs/mfs_vfsops.c b/sys/ufs/mfs/mfs_vfsops.c
index 8ecee1a38d9..c29b924d14b 100644
--- a/sys/ufs/mfs/mfs_vfsops.c
+++ b/sys/ufs/mfs/mfs_vfsops.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mfs_vfsops.c,v 1.44 2012/12/29 14:54:11 beck Exp $	*/
+/*	$OpenBSD: mfs_vfsops.c,v 1.45 2013/01/15 11:20:55 jsing Exp $	*/
 /*	$NetBSD: mfs_vfsops.c,v 1.10 1996/02/09 22:31:28 christos Exp $	*/
 
 /*
@@ -132,16 +132,15 @@ mfs_mount(struct mount *mp, const char *path, void *data,
 	if (checkalias(devvp, makedev(255, mfs_minor), (struct mount *)0))
 		panic("mfs_mount: dup dev");
 	mfs_minor++;
-	mfsp = malloc(sizeof *mfsp, M_MFSNODE, M_WAITOK);
+	mfsp = malloc(sizeof *mfsp, M_MFSNODE, M_WAITOK | M_ZERO);
 	devvp->v_data = mfsp;
 	mfsp->mfs_baseoff = args.base;
 	mfsp->mfs_size = args.size;
 	mfsp->mfs_vnode = devvp;
 	mfsp->mfs_pid = p->p_pid;
-	mfsp->mfs_numbufs = 0;
-	mfsp->mfs_buflist = (struct buf *)0;
+	bufq_init(&mfsp->mfs_bufq, BUFQ_FIFO);
 	if ((error = ffs_mountfs(devvp, mp, p)) != 0) {
-		mfsp->mfs_buflist = (struct buf *)-1;
+		mfsp->mfs_shutdown = 1;
 		vrele(devvp);
 		return (error);
 	}
@@ -175,25 +174,21 @@ mfs_start(struct mount *mp, int flags, struct proc *p)
 	struct vnode *vp = VFSTOUFS(mp)->um_devvp;
 	struct mfsnode *mfsp = VTOMFS(vp);
 	struct buf *bp;
-	int sleepreturn = 0, s;
+	int sleepreturn = 0;
 
 	while (1) {
 		while (1) {
-			s = splbio();
-			bp = mfsp->mfs_buflist;
-			if (bp == NULL || bp == (struct buf *)-1) {
-				splx(s);
+			if (mfsp->mfs_shutdown == 1)
+				break;
+			bp = bufq_dequeue(&mfsp->mfs_bufq);
+			if (bp == NULL)
 				break;
-			}
-			mfsp->mfs_buflist = bp->b_actf;
-			mfsp->mfs_numbufs--;
-			splx(s);
 			mfs_doio(mfsp, bp);
-			wakeup((caddr_t)bp);
-			wakeup(&mfsp->mfs_numbufs);
+			wakeup(bp);
 		}
-		if (bp == (struct buf *)-1)
+		if (mfsp->mfs_shutdown == 1)
 			break;
+
 		/*
 		 * If a non-ignored signal is received, try to unmount.
 		 * If that fails, clear the signal (it has been "processed"),
diff --git a/sys/ufs/mfs/mfs_vnops.c b/sys/ufs/mfs/mfs_vnops.c
index 2d19f1658a3..b66a95f29d6 100644
--- a/sys/ufs/mfs/mfs_vnops.c
+++ b/sys/ufs/mfs/mfs_vnops.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mfs_vnops.c,v 1.43 2012/12/29 14:54:11 beck Exp $	*/
+/*	$OpenBSD: mfs_vnops.c,v 1.44 2013/01/15 11:20:55 jsing Exp $	*/
 /*	$NetBSD: mfs_vnops.c,v 1.8 1996/03/17 02:16:32 christos Exp $	*/
 
 /*
@@ -133,12 +133,6 @@ mfs_strategy(void *v)
 	struct mfsnode *mfsp;
 	struct vnode *vp;
 	struct proc *p = curproc;
-	int bufmax;
-	int s;
-
-	/* Constrain queue to a sensible value. */
-	bufmax = MIN(256, bcstats.kvaslots / 16);
-	bufmax = MIN(bufmax, bcstats.numbufs / 16);
 
 	if (!vfinddev(bp->b_dev, VBLK, &vp) || vp->v_usecount == 0)
 		panic("mfs_strategy: bad dev");
@@ -147,14 +141,8 @@ mfs_strategy(void *v)
 	if (p != NULL && mfsp->mfs_pid == p->p_pid) {
 		mfs_doio(mfsp, bp);
 	} else {
-		s = splbio();
-		while (mfsp->mfs_numbufs > bufmax)
-			tsleep(&mfsp->mfs_numbufs, PRIBIO + 1, "mfsbufs", 0);
-		bp->b_actf = mfsp->mfs_buflist;
-		mfsp->mfs_buflist = bp;
-		mfsp->mfs_numbufs++;
-		splx(s);
-		wakeup((caddr_t)vp);
+		bufq_queue(&mfsp->mfs_bufq, bp);
+		wakeup(vp);
 	}
 	return (0);
 }
@@ -199,42 +187,39 @@ mfs_close(void *v)
 	struct vnode *vp = ap->a_vp;
 	struct mfsnode *mfsp = VTOMFS(vp);
 	struct buf *bp;
-	int error, s;
+	int error;
 
 	/*
 	 * Finish any pending I/O requests.
 	 */
 	while (1) {
-		s = splbio();
-		bp = mfsp->mfs_buflist;
-		if (bp == NULL) {
-			splx(s);
+		bp = bufq_dequeue(&mfsp->mfs_bufq);
+		if (bp == NULL)
 			break;
-		}
-		mfsp->mfs_buflist = bp->b_actf;
-		splx(s);
 		mfs_doio(mfsp, bp);
-		wakeup((caddr_t)bp);
+		wakeup(bp);
 	}
+
 	/*
-	 * On last close of a memory filesystem
-	 * we must invalidate any in core blocks, so that
-	 * we can free up its vnode.
+	 * On last close of a memory filesystem we must invalidate any in
+	 * core blocks, so that we can free up its vnode.
 	 */
 	if ((error = vinvalbuf(vp, V_SAVE, ap->a_cred, ap->a_p, 0, 0)) != 0)
 		return (error);
+
 #ifdef DIAGNOSTIC
 	/*
 	 * There should be no way to have any more buffers on this vnode.
 	 */
-	if (mfsp->mfs_buflist)
+	if (bufq_peek(&mfsp->mfs_bufq))
 		printf("mfs_close: dirty buffers\n");
 #endif
+
 	/*
 	 * Send a request to the filesystem server to exit.
 	 */
-	mfsp->mfs_buflist = (struct buf *)(-1);
-	wakeup((caddr_t)vp);
+	mfsp->mfs_shutdown = 1;
+	wakeup(vp);
 	return (0);
 }
 
@@ -249,9 +234,8 @@ mfs_inactive(void *v)
 #ifdef DIAGNOSTIC
 	struct mfsnode *mfsp = VTOMFS(ap->a_vp);
 
-	if (mfsp->mfs_buflist && mfsp->mfs_buflist != (struct buf *)(-1))
-		panic("mfs_inactive: not inactive (mfs_buflist %p)",
-			mfsp->mfs_buflist);
+	if (mfsp->mfs_shutdown && bufq_peek(&mfsp->mfs_bufq))
+		panic("mfs_inactive: not inactive");
 #endif
 	VOP_UNLOCK(ap->a_vp, 0, ap->a_p);
 	return (0);
diff --git a/sys/ufs/mfs/mfsnode.h b/sys/ufs/mfs/mfsnode.h
index 0c5d89a1a76..644c72a2e8e 100644
--- a/sys/ufs/mfs/mfsnode.h
+++ b/sys/ufs/mfs/mfsnode.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mfsnode.h,v 1.13 2012/12/29 14:54:11 beck Exp $	*/
+/*	$OpenBSD: mfsnode.h,v 1.14 2013/01/15 11:20:55 jsing Exp $	*/
 /*	$NetBSD: mfsnode.h,v 1.3 1996/02/09 22:31:31 christos Exp $	*/
 
 /*
@@ -37,13 +37,13 @@
  */
 
 struct mfsnode {
-	struct	vnode *mfs_vnode;	/* vnode associated with this mfsnode */
+	struct vnode *mfs_vnode;	/* vnode associated with this mfsnode */
+	struct bufq mfs_bufq;		/* bufq for MFS I/O */
 	caddr_t	mfs_baseoff;		/* base of file system in memory */
 	long	mfs_size;		/* size of memory file system */
 	pid_t	mfs_pid;		/* supporting process pid */
 	struct	buf *mfs_buflist;	/* list of I/O requests */
-	long	mfs_numbufs;		/* # of bufs on I/O request list */
-	long	mfs_spare[3];
+	int	mfs_shutdown;		/* shutdown request */
 };
 
 /*