Re-work the handling of incoming I/O in RAIDframe:

- introduce rf_buf_queue_check() which checks to see if there
is work to do in the incoming buffer queue
- rf_RaidIOThread() is now responsible for calling raidstart(), and is
also now the only place that calls raidstart()
- raidstrategy() now just queues requests in buf_queue
and signals rf_RaidIOThread() that work has arrived

Hopefully addresses PR#30233

sys/dev/raidframe/rf_engine.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: rf_engine.c,v 1.35 2005/02/27 00:27:44 perry Exp $	*/
+/*	$NetBSD: rf_engine.c,v 1.36 2005/09/25 19:47:17 oster Exp $	*/
 /*
  * Copyright (c) 1995 Carnegie-Mellon University.
  * All rights reserved.
@@ -55,7 +55,7 @@
  ****************************************************************************/
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rf_engine.c,v 1.35 2005/02/27 00:27:44 perry Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rf_engine.c,v 1.36 2005/09/25 19:47:17 oster Exp $");
 
 #include <sys/errno.h>
 
@@ -67,6 +67,7 @@ __KERNEL_RCSID(0, "$NetBSD: rf_engine.c,v 1.35 2005/02/27 00:27:44 perry Exp $")
 #include "rf_dagutils.h"
 #include "rf_shutdown.h"
 #include "rf_raid.h"
+#include "rf_kintf.h"
 
 static void rf_ShutdownEngine(void *);
 static void DAGExecutionThread(RF_ThreadArg_t arg);
@@ -825,11 +826,13 @@ DAGExecutionThread(RF_ThreadArg_t arg)
 }
 
 /*
- * rf_RaidIOThread() -- When I/O to a component completes,
+ * rf_RaidIOThread() -- When I/O to a component begins, raidstrategy()
- * KernelWakeupFunc() puts the completed request onto raidPtr->iodone
+ * puts the I/O on a buf_queue, and then signals raidPtr->iodone.  If
- * TAILQ.  This function looks after requests on that queue by calling
+ * necessary, this function calls raidstart() to initiate the I/O.
- * rf_DiskIOComplete() for the request, and by calling any required
+ * When I/O to a component completes, KernelWakeupFunc() puts the
- * CompleteFunc for the request.
+ * completed request onto raidPtr->iodone TAILQ.  This function looks
+ * after requests on that queue by calling rf_DiskIOComplete() for the
+ * request, and by calling any required CompleteFunc for the request.  
  */
 
 static void
@@ -846,7 +849,8 @@ rf_RaidIOThread(RF_ThreadArg_t arg)
 
 	while (!raidPtr->shutdown_raidio) {
 		/* if there is nothing to do, then snooze. */
-		if (TAILQ_EMPTY(&(raidPtr->iodone))) {
+		if (TAILQ_EMPTY(&(raidPtr->iodone)) &&
+		    rf_buf_queue_check(raidPtr->raidid)) {
 			ltsleep(&(raidPtr->iodone), PRIBIO, "raidiow", 0,
 				&(raidPtr->iodone_lock));
 		}
@@ -859,6 +863,12 @@ rf_RaidIOThread(RF_ThreadArg_t arg)
 			(req->CompleteFunc) (req->argument, req->error);
 			simple_lock(&(raidPtr->iodone_lock));
 		}
+
+		/* process any pending outgoing IO */
+		simple_unlock(&(raidPtr->iodone_lock));
+		raidstart(raidPtr);
+		simple_lock(&(raidPtr->iodone_lock));
+
 	}
 
 	/* Let rf_ShutdownEngine know that we're done... */

sys/dev/raidframe/rf_netbsd.h

@@ -1,4 +1,4 @@
-/*	$NetBSD: rf_netbsd.h,v 1.23 2005/05/29 22:03:09 christos Exp $	*/
+/*	$NetBSD: rf_netbsd.h,v 1.24 2005/09/25 19:47:17 oster Exp $	*/
 
 /*-
  * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
@@ -90,6 +90,7 @@ struct RF_Pools_s {
 
 extern struct RF_Pools_s rf_pools;
 void rf_pool_init(struct pool *, size_t, const char *, size_t, size_t);
+int rf_buf_queue_check(int);
 
 /* XXX probably belongs in a different .h file. */
 typedef struct RF_AutoConfig_s {

sys/dev/raidframe/rf_netbsdkintf.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: rf_netbsdkintf.c,v 1.189 2005/09/24 22:51:55 oster Exp $	*/
+/*	$NetBSD: rf_netbsdkintf.c,v 1.190 2005/09/25 19:47:17 oster Exp $	*/
 /*-
  * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -146,7 +146,7 @@
  ***********************************************************/
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rf_netbsdkintf.c,v 1.189 2005/09/24 22:51:55 oster Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rf_netbsdkintf.c,v 1.190 2005/09/25 19:47:17 oster Exp $");
 
 #include <sys/param.h>
 #include <sys/errno.h>
@@ -735,7 +735,8 @@ raidstrategy(struct buf *bp)
 	/* stuff it onto our queue */
 	BUFQ_PUT(&rs->buf_queue, bp);
 
-	raidstart(raidPtrs[raidID]);
+	/* scheduled the IO to happen at the next convenient time */
+	wakeup(&(raidPtrs[raidID]->iodone));
 
 	splx(s);
 }
@@ -3330,3 +3331,23 @@ rf_pool_init(struct pool *p, size_t size, const char *w_chan,
 	pool_prime(p, xmin);
 	pool_setlowat(p, xmin);
 }
+
+/*
+ * rf_buf_queue_check(int raidid) -- looks into the buf_queue to see
+ * if there is IO pending and if that IO could possibly be done for a
+ * given RAID set.  Returns 0 if IO is waiting and can be done, 1
+ * otherwise.
+ *
+ */
+
+int
+rf_buf_queue_check(int raidid)
+{
+	if ((BUFQ_PEEK(&(raid_softc[raidid].buf_queue)) != NULL) &&
+	    raidPtrs[raidid]->openings > 0) {
+		/* there is work to do */
+		return 0;
+	} 
+	/* default is nothing to do */
+	return 1;
+}

sys/dev/raidframe/rf_states.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: rf_states.c,v 1.38 2005/02/27 00:27:45 perry Exp $	*/
+/*	$NetBSD: rf_states.c,v 1.39 2005/09/25 19:47:17 oster Exp $	*/
 /*
  * Copyright (c) 1995 Carnegie-Mellon University.
  * All rights reserved.
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rf_states.c,v 1.38 2005/02/27 00:27:45 perry Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rf_states.c,v 1.39 2005/09/25 19:47:17 oster Exp $");
 
 #include <sys/errno.h>
 
@@ -235,8 +235,7 @@ rf_State_LastState(RF_RaidAccessDesc_t *desc)
 	((RF_Raid_t *) desc->raidPtr)->openings++;
 	RF_UNLOCK_MUTEX(((RF_Raid_t *) desc->raidPtr)->mutex);
 
-	/* wake up any pending IO */
+	wakeup(&(desc->raidPtr->iodone));
-	raidstart(((RF_Raid_t *) desc->raidPtr));
 
 	/* printf("Calling biodone on 0x%x\n",desc->bp); */
 	biodone(desc->bp);	/* access came through ioctl */