From 847bd808107e95429b1c1146aab63fa8ef37e579 Mon Sep 17 00:00:00 2001
From: John Baldwin <jhb@FreeBSD.org>
Date: Mon, 21 Jul 2008 18:43:02 +0000
Subject: [PATCH] Allocate a single CCB at the start of the main loop of the
 RAID monitoring kthread of the mpt(4) driver that hangs around for the entire
 lifetime of the thread.  Previously the driver would allocate a new CCB using
 M_WAITOK with a lock held each time it updated its state.  While here, use
 the CAM API for allocating a CCB rather than raw malloc(9).

Reviewed by:	scottl
MFC after:	1 week
---
 sys/dev/mpt/mpt_raid.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sys/dev/mpt/mpt_raid.c b/sys/dev/mpt/mpt_raid.c
index 2b7c129064e..cde0fec0b65 100644
--- a/sys/dev/mpt/mpt_raid.c
+++ b/sys/dev/mpt/mpt_raid.c
@@ -52,6 +52,7 @@ __FBSDID("$FreeBSD$");
 #include <cam/cam.h>
 #include <cam/cam_ccb.h>
 #include <cam/cam_sim.h>
+#include <cam/cam_xpt_periph.h>
 #include <cam/cam_xpt_sim.h>
 
 #if __FreeBSD_version < 500000
@@ -657,17 +658,18 @@ static void
 mpt_cam_rescan_callback(struct cam_periph *periph, union ccb *ccb)
 {
 	xpt_free_path(ccb->ccb_h.path);
-	free(ccb, M_DEVBUF);
 }
 
 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) {
 
@@ -695,18 +697,15 @@ mpt_raid_thread(void *arg)
 		}
 
 		if (mpt->raid_rescan != 0) {
-			union ccb *ccb;
 			struct cam_path *path;
 			int error;
 
 			mpt->raid_rescan = 0;
 
-			ccb = malloc(sizeof(*ccb), M_DEVBUF, M_WAITOK);
 			error = xpt_create_path(&path, xpt_periph,
 			    cam_sim_path(mpt->phydisk_sim),
 			    CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
 			if (error != CAM_REQ_CMP) {
-				free(ccb, M_DEVBUF);
 				mpt_prt(mpt, "Unable to rescan RAID Bus!\n");
 			} else {
 				xpt_setup_ccb(&ccb->ccb_h, path, 5);
@@ -719,6 +718,7 @@ mpt_raid_thread(void *arg)
 			}
 		}
 	}
+	xpt_free_ccb(ccb);
 	mpt->raid_thread = NULL;
 	wakeup(&mpt->raid_thread);
 	MPT_UNLOCK(mpt);