From 46990862ab1b1af1e8137c5fc2c00ad554bcbd5b Mon Sep 17 00:00:00 2001
From: John Baldwin <jhb@FreeBSD.org>
Date: Thu, 21 May 2009 12:36:40 +0000
Subject: [PATCH] Largely revert the earlier change to use a single CCB for the
 RAID recovery thread.  Multiple RAID events in quick succession can cause an
 additional bus rescan to be scheduled before an earlier scan has completed. 
 In this case the driver was attempting to use the same CCB storage for two
 requests.

PR:		kern/130330
Reviewed by:	Riccardo Torrini  riccardo.torrini | esaote com
MFC after:	1 week
---
 sys/dev/mpt/mpt_raid.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/sys/dev/mpt/mpt_raid.c b/sys/dev/mpt/mpt_raid.c
index 0d5e03a730aa..6b7eb7b46c46 100644
--- a/sys/dev/mpt/mpt_raid.c
+++ b/sys/dev/mpt/mpt_raid.c
@@ -658,19 +658,19 @@ mpt_terminate_raid_thread(struct mpt_softc *mpt)
 static void
 mpt_cam_rescan_callback(struct cam_periph *periph, union ccb *ccb)
 {
+
 	xpt_free_path(ccb->ccb_h.path);
+	xpt_free_ccb(ccb);
 }
 
 static void
 mpt_raid_thread(void *arg)
 {
 	struct mpt_softc *mpt;
-	union ccb *ccb;
 	int firstrun;
 
 	mpt = (struct mpt_softc *)arg;
 	firstrun = 1;
-	ccb = xpt_alloc_ccb();
 	MPT_LOCK(mpt);
 	while (mpt->shutdwn_raid == 0) {
 
@@ -698,15 +698,21 @@ mpt_raid_thread(void *arg)
 		}
 
 		if (mpt->raid_rescan != 0) {
+			union ccb *ccb;
 			struct cam_path *path;
 			int error;
 
 			mpt->raid_rescan = 0;
+			MPT_UNLOCK(mpt);
 
+			ccb = xpt_alloc_ccb();
+
+			MPT_LOCK(mpt);
 			error = xpt_create_path(&path, xpt_periph,
 			    cam_sim_path(mpt->phydisk_sim),
 			    CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
 			if (error != CAM_REQ_CMP) {
+				xpt_free_ccb(ccb);
 				mpt_prt(mpt, "Unable to rescan RAID Bus!\n");
 			} else {
 				xpt_setup_ccb(&ccb->ccb_h, path, 5);
@@ -719,7 +725,6 @@ mpt_raid_thread(void *arg)
 			}
 		}
 	}
-	xpt_free_ccb(ccb);
 	mpt->raid_thread = NULL;
 	wakeup(&mpt->raid_thread);
 	MPT_UNLOCK(mpt);