switch ss over to using xshandlers for queuing io. this brings it into line

with sd/cd/st.

largely a mechanical change, untested due to a complete lack of hardware
anywhere.

ok krw@ matthew@

4 files changed, 39 insertions, 56 deletions

diff --git a/sys/scsi/ss.c b/sys/scsi/ss.c
index adfab839b45..ee4a49352d0 100644
--- a/sys/scsi/ss.c
+++ b/sys/scsi/ss.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ss.c,v 1.76 2010/06/26 23:24:45 guenther Exp $	*/
+/*	$OpenBSD: ss.c,v 1.77 2010/06/30 00:02:00 dlg Exp $	*/
 /*	$NetBSD: ss.c,v 1.10 1996/05/05 19:52:55 christos Exp $	*/
 
 /*
@@ -111,7 +111,7 @@ struct  quirkdata ss_gen_quirks = {
 };
 
 void    ssstrategy(struct buf *);
-void    ssstart(void *);
+void    ssstart(struct scsi_xfer *);
 void	ssdone(struct scsi_xfer *);
 void	ssminphys(struct buf *);
 
@@ -254,7 +254,7 @@ struct cfdriver ss_cd = {
 
 struct scsi_device ss_switch = {
 	NULL,
-	ssstart,
+	NULL,
 	NULL,
 	NULL,
 };
@@ -353,9 +353,8 @@ ssattach(parent, self, aux)
 	/* XXX fill in the rest of the scan_io struct by calling the
 	   compute_sizes routine */
 
-	mtx_init(&ss->sc_start_mtx, IPL_BIO);
-
-	timeout_set(&ss->timeout, ssstart, ss);
+	scsi_xsh_set(&ss->xsh, sc_link, ssstart);
+	timeout_set(&ss->timeout, (void (*)(void *))scsi_xsh_add, &ss->xsh);
 
 	/* Set up the buf queue for this device. */
 	ss->sc_bufq = bufq_init(BUFQ_DEFAULT);
@@ -591,7 +590,7 @@ ssstrategy(bp)
 	 * not doing anything, otherwise just wait for completion
 	 * (All a bit silly if we're only allowing 1 open but..)
 	 */
-	ssstart(ss);
+	scsi_xsh_add(&ss->xsh);
 
 	device_unref(&ss->sc_dev);
 	return;
@@ -625,60 +624,45 @@ done:
  * ssstart() is called at splbio
  */
 void
-ssstart(v)
-	void *v;
+ssstart(struct scsi_xfer *xs)
 {
-	struct ss_softc *ss = v;
-	struct scsi_link *sc_link = ss->sc_link;
-	struct scsi_xfer *xs;
+	struct scsi_link *sc_link = xs->sc_link;
+	struct ss_softc *ss = sc_link->device_softc;
 	struct buf *bp;
 	struct scsi_r_scanner *cdb;
 
 	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);
+	bp = BUFQ_DEQUEUE(ss->sc_bufq);
+	if (bp == NULL) {
+		scsi_xs_put(xs);
 		return;
 	}
-	mtx_leave(&ss->sc_start_mtx);
-	CLR(ss->flags, SSF_WAITING);
-restart:
-	while (!ISSET(ss->flags, SSF_WAITING) &&
-	    (bp = BUFQ_DEQUEUE(ss->sc_bufq)) != NULL) {
-		xs = scsi_xs_get(sc_link, SCSI_NOSLEEP);
-		if (xs == NULL)
-			break;
 
-		if (ss->special.read) {
-			(ss->special.read)(ss, xs, bp);
-		} else {
-			cdb = (struct scsi_r_scanner *)xs->cmd;
-			xs->cmdlen = sizeof(*cdb);
+	if (ss->special.read) {
+		(ss->special.read)(ss, xs, bp);
+	} else {
+		cdb = (struct scsi_r_scanner *)xs->cmd;
+		xs->cmdlen = sizeof(*cdb);
 
-			cdb->opcode = READ_BIG;
-			_lto3b(bp->b_bcount, cdb->len);
+		cdb->opcode = READ_BIG;
+		_lto3b(bp->b_bcount, cdb->len);
 
-			xs->data = bp->b_data;
-			xs->datalen = bp->b_bcount;
-			xs->flags |= SCSI_DATA_IN;
-			xs->retries = 0;
-			xs->timeout = 100000;
-			xs->done = ssdone;
-			xs->cookie = bp;
+		xs->data = bp->b_data;
+		xs->datalen = bp->b_bcount;
+		xs->flags |= SCSI_DATA_IN;
+		xs->retries = 0;
+		xs->timeout = 100000;
+		xs->done = ssdone;
+		xs->cookie = bp;
 
-			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;
+		scsi_xs_exec(xs);
 	}
-	mtx_leave(&ss->sc_start_mtx);
+
+	if (ISSET(ss->flags, SSF_WAITING))
+		CLR(ss->flags, SSF_WAITING);
+	else if (BUFQ_PEEK(ss->sc_bufq))
+		scsi_xsh_add(&ss->xsh);
 }
 
 void
@@ -698,7 +682,7 @@ ssdone(struct scsi_xfer *xs)
 		/* The adapter is busy, requeue the buf and try it later. */
 		BUFQ_REQUEUE(ss->sc_bufq, bp);
 		scsi_xs_put(xs);
-		SET(ss->flags, SSF_WAITING); /* break out of cdstart loop */
+		SET(ss->flags, SSF_WAITING);
 		timeout_add(&ss->timeout, 1);
 		return;
 
diff --git a/sys/scsi/ss_mustek.c b/sys/scsi/ss_mustek.c
index e70d91463ea..42f13c99de7 100644
--- a/sys/scsi/ss_mustek.c
+++ b/sys/scsi/ss_mustek.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ss_mustek.c,v 1.24 2010/06/26 23:24:45 guenther Exp $	*/
+/*	$OpenBSD: ss_mustek.c,v 1.25 2010/06/30 00:02:00 dlg Exp $	*/
 /*	$NetBSD: ss_mustek.c,v 1.4 1996/05/05 19:52:57 christos Exp $	*/
 
 /*
@@ -487,7 +487,7 @@ mustek_read_done(struct scsi_xfer *xs)
 		/* The adapter is busy, requeue the buf and try it later. */
 		BUFQ_REQUEUE(ss->sc_bufq, bp);
                 scsi_xs_put(xs);
-		SET(ss->flags, SSF_WAITING); /* break out of cdstart loop */
+		SET(ss->flags, SSF_WAITING);
 		timeout_add(&ss->timeout, 1);
 		return;
 
diff --git a/sys/scsi/ss_scanjet.c b/sys/scsi/ss_scanjet.c
index 4e200228b71..ef82988c0b1 100644
--- a/sys/scsi/ss_scanjet.c
+++ b/sys/scsi/ss_scanjet.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ss_scanjet.c,v 1.41 2010/06/26 23:24:45 guenther Exp $	*/
+/*	$OpenBSD: ss_scanjet.c,v 1.42 2010/06/30 00:02:00 dlg Exp $	*/
 /*	$NetBSD: ss_scanjet.c,v 1.6 1996/05/18 22:58:01 christos Exp $	*/
 
 /*
@@ -325,7 +325,7 @@ scanjet_read_done(struct scsi_xfer *xs)
 		/* The adapter is busy, requeue the buf and try it later. */
 		BUFQ_REQUEUE(ss->sc_bufq, bp);
                 scsi_xs_put(xs);
-		SET(ss->flags, SSF_WAITING); /* break out of cdstart loop */
+		SET(ss->flags, SSF_WAITING);
 		timeout_add(&ss->timeout, 1);
 		return;
 
diff --git a/sys/scsi/ssvar.h b/sys/scsi/ssvar.h
index ba6f9e5c8b5..6c39529c139 100644
--- a/sys/scsi/ssvar.h
+++ b/sys/scsi/ssvar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ssvar.h,v 1.17 2010/06/01 15:27:16 thib Exp $	*/
+/*	$OpenBSD: ssvar.h,v 1.18 2010/06/30 00:02:00 dlg Exp $	*/
 /*	$NetBSD: ssvar.h,v 1.2 1996/03/30 21:47:11 christos Exp $	*/
 
 /*
@@ -74,8 +74,7 @@ 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 sc_start_mtx;
-	u_int sc_start_count;
+	struct scsi_xshandler xsh;
 };
 
 /*