Bring mutex protections to ststart, cdstart and ssstart, as already

done in sd. Make names consistant across all three.

ok dlg@ tested (cd) & ok beck@

4 files changed, 84 insertions, 40 deletions

diff --git a/sys/scsi/cd.c b/sys/scsi/cd.c
index 2ea0cbddcef..918e3f77f05 100644
--- a/sys/scsi/cd.c
+++ b/sys/scsi/cd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cd.c,v 1.159 2010/01/11 00:44:40 krw Exp $	*/
+/*	$OpenBSD: cd.c,v 1.160 2010/01/11 08:56:17 krw Exp $	*/
 /*	$NetBSD: cd.c,v 1.100 1997/04/02 02:29:30 mycroft Exp $	*/
 
 /*
@@ -110,8 +110,9 @@ struct cd_softc {
 		daddr64_t disksize;	/* total number sectors */
 	} sc_params;
 	struct buf sc_buf_queue;
-	struct mutex sc_queue_mtx;
+	struct mutex sc_buf_mtx;
 	struct mutex sc_start_mtx;
+	u_int sc_start_count;
 	struct timeout sc_timeout;
 	void *sc_cdpwrhook;		/* our power hook */
 };
@@ -215,7 +216,7 @@ cdattach(struct device *parent, struct device *self, void *aux)
 
 	SC_DEBUG(sc_link, SDEV_DB2, ("cdattach:\n"));
 
-	mtx_init(&sc->sc_queue_mtx, IPL_BIO);
+	mtx_init(&sc->sc_buf_mtx, IPL_BIO);
 	mtx_init(&sc->sc_start_mtx, IPL_BIO);
 
 	/*
@@ -525,9 +526,9 @@ cdstrategy(struct buf *bp)
 	/*
 	 * Place it in the queue of disk activities for this disk
 	 */
-	mtx_enter(&sc->sc_queue_mtx);
+	mtx_enter(&sc->sc_buf_mtx);
 	disksort(&sc->sc_buf_queue, bp);
-	mtx_leave(&sc->sc_queue_mtx);
+	mtx_leave(&sc->sc_buf_mtx);
 
 	/*
 	 * Tell the device to get going on the transfer if it's
@@ -557,13 +558,13 @@ cd_buf_dequeue(struct cd_softc *sc)
 {
 	struct buf *bp;
 
-	mtx_enter(&sc->sc_queue_mtx);
+	mtx_enter(&sc->sc_buf_mtx);
 	bp = sc->sc_buf_queue.b_actf;
 	if (bp != NULL)
 		sc->sc_buf_queue.b_actf = bp->b_actf;
 	if (sc->sc_buf_queue.b_actf == NULL)
 		sc->sc_buf_queue.b_actb = &sc->sc_buf_queue.b_actf;
-	mtx_leave(&sc->sc_queue_mtx);
+	mtx_leave(&sc->sc_buf_mtx);
 
 	return (bp);
 }
@@ -571,12 +572,12 @@ cd_buf_dequeue(struct cd_softc *sc)
 void
 cd_buf_requeue(struct cd_softc *sc, struct buf *bp)
 {
-	mtx_enter(&sc->sc_queue_mtx);
+	mtx_enter(&sc->sc_buf_mtx);
 	bp->b_actf = sc->sc_buf_queue.b_actf;
 	sc->sc_buf_queue.b_actf = bp;
 	if (bp->b_actf == NULL)
 		sc->sc_buf_queue.b_actb = &bp->b_actf;
-	mtx_leave(&sc->sc_queue_mtx);
+	mtx_leave(&sc->sc_buf_mtx);
 }
 
 /*
@@ -610,10 +611,15 @@ cdstart(void *v)
 	int s;
 
 	SC_DEBUG(sc_link, SDEV_DB2, ("cdstart\n"));
-	/*
-	 * Check if the device has room for another command
-	 */
 
+	mtx_enter(&sc->sc_start_mtx);
+	sc->sc_start_count++;
+	if (sc->sc_start_count > 1) {
+		mtx_leave(&sc->sc_start_mtx);
+		return;
+	}
+	mtx_leave(&sc->sc_start_mtx);
+restart:
 	CLR(sc->sc_flags, CDF_WAITING);
 	while (!ISSET(sc->sc_flags, CDF_WAITING) &&
 	    (bp = cd_buf_dequeue(sc)) != NULL) {
@@ -694,6 +700,14 @@ cdstart(void *v)
 
 		scsi_xs_exec(xs);
 	}
+	mtx_enter(&sc->sc_start_mtx);
+	sc->sc_start_count--;
+	if (sc->sc_start_count != 0) {
+		sc->sc_start_count = 1;
+		mtx_leave(&sc->sc_start_mtx);
+		goto restart;
+	}
+	mtx_leave(&sc->sc_start_mtx);
 }
 
 void
diff --git a/sys/scsi/ss.c b/sys/scsi/ss.c
index 900431f23a3..60095431053 100644
--- a/sys/scsi/ss.c
+++ b/sys/scsi/ss.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ss.c,v 1.66 2010/01/09 21:12:06 dlg Exp $	*/
+/*	$OpenBSD: ss.c,v 1.67 2010/01/11 08:56:17 krw Exp $	*/
 /*	$NetBSD: ss.c,v 1.10 1996/05/05 19:52:55 christos Exp $	*/
 
 /*
@@ -354,8 +354,8 @@ ssattach(parent, self, aux)
 	/* XXX fill in the rest of the scan_io struct by calling the
 	   compute_sizes routine */
 
-	mtx_init(&ss->queue_mtx, IPL_BIO);
-	mtx_init(&ss->start_mtx, IPL_BIO);
+	mtx_init(&ss->sc_buf_mtx, IPL_BIO);
+	mtx_init(&ss->sc_start_mtx, IPL_BIO);
 
 	timeout_set(&ss->timeout, ssstart, ss);
 
@@ -610,13 +610,13 @@ ss_buf_enqueue(struct ss_softc *ss, struct buf *bp)
 {
 	struct buf *dp;
 
-	mtx_enter(&ss->queue_mtx);
+	mtx_enter(&ss->sc_buf_mtx);
 	dp = &ss->buf_queue;
 	bp->b_actf = NULL;
 	bp->b_actb = dp->b_actb;
 	*dp->b_actb = bp;
 	dp->b_actb = &bp->b_actf;
-	mtx_leave(&ss->queue_mtx);
+	mtx_leave(&ss->sc_buf_mtx);
 }
 
 struct buf *
@@ -624,13 +624,13 @@ ss_buf_dequeue(struct ss_softc *ss)
 {
 	struct buf *bp;
 
-	mtx_enter(&ss->queue_mtx);
+	mtx_enter(&ss->sc_buf_mtx);
 	bp = ss->buf_queue.b_actf;
 	if (bp != NULL)
 		ss->buf_queue.b_actf = bp->b_actf;
 	if (ss->buf_queue.b_actf == NULL)
 		ss->buf_queue.b_actb = &ss->buf_queue.b_actf;
-	mtx_leave(&ss->queue_mtx);
+	mtx_leave(&ss->sc_buf_mtx);
 
 	return (bp);
 }
@@ -638,12 +638,12 @@ ss_buf_dequeue(struct ss_softc *ss)
 void
 ss_buf_requeue(struct ss_softc *ss, struct buf *bp)
 {
-	mtx_enter(&ss->queue_mtx);
+	mtx_enter(&ss->sc_buf_mtx);
 	bp->b_actf = ss->buf_queue.b_actf;
 	ss->buf_queue.b_actf = bp;
 	if (bp->b_actf == NULL)
 		ss->buf_queue.b_actb = &bp->b_actf;
-	mtx_leave(&ss->queue_mtx);
+	mtx_leave(&ss->sc_buf_mtx);
 }
 
 
@@ -673,6 +673,14 @@ ssstart(v)
 
 	SC_DEBUG(sc_link, SDEV_DB2, ("ssstart\n"));
 
+	mtx_enter(&ss->sc_start_mtx);
+	ss->sc_start_count++;
+	if (ss->sc_start_count > 1) {
+		mtx_leave(&ss->sc_start_mtx);
+		return;
+	}
+	mtx_leave(&ss->sc_start_mtx);
+restart:
 	CLR(ss->flags, SSF_WAITING);
 	while (!ISSET(ss->flags, SSF_WAITING) &&
 	    (bp = ss_buf_dequeue(ss)) != NULL) {
@@ -701,6 +709,14 @@ ssstart(v)
 			scsi_xs_exec(xs);
 		}
 	}
+	mtx_enter(&ss->sc_start_mtx);
+	ss->sc_start_count--;
+	if (ss->sc_start_count != 0) {
+		ss->sc_start_count = 1;
+		mtx_leave(&ss->sc_start_mtx);
+		goto restart;
+	}
+	mtx_leave(&ss->sc_start_mtx);
 }
 
 void
diff --git a/sys/scsi/ssvar.h b/sys/scsi/ssvar.h
index 7af6756a314..6f1f783eefe 100644
--- a/sys/scsi/ssvar.h
+++ b/sys/scsi/ssvar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ssvar.h,v 1.14 2010/01/09 21:12:06 dlg Exp $	*/
+/*	$OpenBSD: ssvar.h,v 1.15 2010/01/11 08:56:17 krw Exp $	*/
 /*	$NetBSD: ssvar.h,v 1.2 1996/03/30 21:47:11 christos Exp $	*/
 
 /*
@@ -74,8 +74,9 @@ struct ss_softc {
 	const struct quirkdata *quirkdata; /* if we have a rogue entry */
 	struct ss_special special;	/* special handlers for spec. devices */
 	struct timeout timeout;
-	struct mutex queue_mtx;
-	struct mutex start_mtx;
+	struct mutex sc_buf_mtx;
+	struct mutex sc_start_mtx;
+	u_int sc_start_count;
 };
 
 struct buf *ss_buf_dequeue(struct ss_softc *);
diff --git a/sys/scsi/st.c b/sys/scsi/st.c
index 6525da556ff..9aca15a5a79 100644
--- a/sys/scsi/st.c
+++ b/sys/scsi/st.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: st.c,v 1.89 2010/01/09 21:12:06 dlg Exp $	*/
+/*	$OpenBSD: st.c,v 1.90 2010/01/11 08:56:17 krw Exp $	*/
 /*	$NetBSD: st.c,v 1.71 1997/02/21 23:03:49 thorpej Exp $	*/
 
 /*
@@ -218,8 +218,9 @@ struct st_softc {
 
 	struct buf buf_queue;		/* the queue of pending IO operations */
 	struct timeout sc_timeout;
-	struct mutex queue_mtx;
-	struct mutex start_mtx;
+	struct mutex sc_buf_mtx;
+	struct mutex sc_start_mtx;
+	u_int sc_start_count;
 };
 
 
@@ -339,8 +340,8 @@ stattach(struct device *parent, struct device *self, void *aux)
 	st_identify_drive(st, sa->sa_inqbuf);
 	printf("\n");
 
-	mtx_init(&st->queue_mtx, IPL_BIO);
-	mtx_init(&st->start_mtx, IPL_BIO);
+	mtx_init(&st->sc_buf_mtx, IPL_BIO);
+	mtx_init(&st->sc_start_mtx, IPL_BIO);
 
 	timeout_set(&st->sc_timeout, ststart, st);
 	
@@ -919,13 +920,13 @@ st_buf_enqueue(struct st_softc *st, struct buf *bp)
 {
 	struct buf *dp;
 
-	mtx_enter(&st->queue_mtx);
+	mtx_enter(&st->sc_buf_mtx);
 	dp = &st->buf_queue;
 	bp->b_actf = NULL;
 	bp->b_actb = dp->b_actb;
 	*dp->b_actb = bp;
 	dp->b_actb = &bp->b_actf;
-	mtx_leave(&st->queue_mtx);
+	mtx_leave(&st->sc_buf_mtx);
 }
 
 struct buf *
@@ -933,13 +934,13 @@ st_buf_dequeue(struct st_softc *st)
 {
 	struct buf *bp;
 
-	mtx_enter(&st->queue_mtx);
+	mtx_enter(&st->sc_buf_mtx);
 	bp = st->buf_queue.b_actf;
 	if (bp != NULL)
 		st->buf_queue.b_actf = bp->b_actf;
 	if (st->buf_queue.b_actf == NULL)
 		st->buf_queue.b_actb = &st->buf_queue.b_actf;
-	mtx_leave(&st->queue_mtx);
+	mtx_leave(&st->sc_buf_mtx);
 
 	return (bp);
 }
@@ -947,12 +948,12 @@ st_buf_dequeue(struct st_softc *st)
 void
 st_buf_requeue(struct st_softc *st, struct buf *bp)
 {
-	mtx_enter(&st->queue_mtx);
+	mtx_enter(&st->sc_buf_mtx);
 	bp->b_actf = st->buf_queue.b_actf;
 	st->buf_queue.b_actf = bp;
 	if (bp->b_actf == NULL)
 		st->buf_queue.b_actb = &bp->b_actf;
-	mtx_leave(&st->queue_mtx);
+	mtx_leave(&st->sc_buf_mtx);
 }
 
 
@@ -985,11 +986,14 @@ ststart(void *v)
 	if (st->flags & ST_DYING)
 		return;
 
-	/*
-	 * See if there is a buf to do and we are not already
-	 * doing one
-	 */
-
+	mtx_enter(&st->sc_start_mtx);
+	st->sc_start_count++;
+	if (st->sc_start_count > 1) {
+		mtx_leave(&st->sc_start_mtx);
+		return;
+	}
+	mtx_leave(&st->sc_start_mtx);
+restart:
 	CLR(st->flags, ST_WAITING);
 	while (!ISSET(st->flags, ST_WAITING) &&
 	    (bp = st_buf_dequeue(st)) != NULL) {
@@ -1114,6 +1118,15 @@ ststart(void *v)
 		 */
 		scsi_xs_exec(xs);
 	} /* go back and see if we can cram more work in.. */
+
+	mtx_enter(&st->sc_start_mtx);
+	st->sc_start_count--;
+	if (st->sc_start_count != 0) {
+		st->sc_start_count = 1;
+		mtx_leave(&st->sc_start_mtx);
+		goto restart;
+	}
+	mtx_leave(&st->sc_start_mtx);
 }
 
 void