From 4c8bc9a2426dee5093816cbf17783ee6e59ae87d Mon Sep 17 00:00:00 2001
From: Matthew Dillon <dillon@dragonflybsd.org>
Date: Sun, 3 Jun 2007 11:52:09 +0000
Subject: [PATCH] Part 1/2: Add a sanity check to the NATA interrupt code to
 assert that the command has actually been issued.

---
 sys/dev/disk/nata/ata-all.c   | 19 +++++++++++++++----
 sys/dev/disk/nata/ata-all.h   |  4 +++-
 sys/dev/disk/nata/ata-queue.c |  8 +++++++-
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/sys/dev/disk/nata/ata-all.c b/sys/dev/disk/nata/ata-all.c
index 76638ac094..7d88309146 100644
--- a/sys/dev/disk/nata/ata-all.c
+++ b/sys/dev/disk/nata/ata-all.c
@@ -24,7 +24,7 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * $FreeBSD: src/sys/dev/ata/ata-all.c,v 1.273 2006/05/12 05:04:40 jhb Exp $
- * $DragonFly: src/sys/dev/disk/nata/ata-all.c,v 1.10 2007/06/01 00:31:14 dillon Exp $
+ * $DragonFly: src/sys/dev/disk/nata/ata-all.c,v 1.11 2007/06/03 11:52:09 dillon Exp $
  */
 
 #include "opt_ata.h"
@@ -317,13 +317,24 @@ ata_interrupt(void *data)
 
     spin_lock_wr(&ch->state_mtx);
     do {
-	/* ignore interrupt if its not for us */
+	/*
+	 * Ignore interrupt if its not for us.  This may also have the
+	 * side effect of processing events unrelated to I/O requests.
+	 */
 	if (ch->hw.status && !ch->hw.status(ch->dev))
 	    break;
 
-	/* do we have a running request */
-	if (!(request = ch->running))
+	/*
+	 * Check if we have a running request, and make sure it has been
+	 * completely queued.  Otherwise the channel status may indicate
+	 * not-busy when, in fact, the command had not yet been issued.
+	 */
+	if ((request = ch->running) == NULL)
+	    break;
+	if ((request->flags & ATA_R_HWCMDQUEUED) == 0) {
+	    kprintf("ata_interrupt: early interrupt\n");
 	    break;
+	}
 
 	/* XXX TGEN Ignore weird ATAPI+DMA interrupts on SMP */
 	if (ch->dma && (request->flags & ATA_R_ATAPI)) {
diff --git a/sys/dev/disk/nata/ata-all.h b/sys/dev/disk/nata/ata-all.h
index 7fcf7a4f66..5564712d42 100644
--- a/sys/dev/disk/nata/ata-all.h
+++ b/sys/dev/disk/nata/ata-all.h
@@ -24,7 +24,7 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * $FreeBSD: src/sys/dev/ata/ata-all.h,v 1.118 2006/06/28 09:59:09 sos Exp $
- * $DragonFly: src/sys/dev/disk/nata/ata-all.h,v 1.5 2007/06/01 00:31:14 dillon Exp $
+ * $DragonFly: src/sys/dev/disk/nata/ata-all.h,v 1.6 2007/06/03 11:52:09 dillon Exp $
  */
 
 #include <sys/param.h>
@@ -374,6 +374,8 @@ struct ata_request {
 #define         ATA_R_THREAD            0x00000800
 #define         ATA_R_DIRECT            0x00001000
 
+#define		ATA_R_HWCMDQUEUED	0x00010000
+
 #define         ATA_R_DEBUG             0x10000000
 #define         ATA_R_DANGER1           0x20000000
 #define         ATA_R_DANGER2           0x40000000
diff --git a/sys/dev/disk/nata/ata-queue.c b/sys/dev/disk/nata/ata-queue.c
index 114cd84543..f10e751674 100644
--- a/sys/dev/disk/nata/ata-queue.c
+++ b/sys/dev/disk/nata/ata-queue.c
@@ -24,7 +24,7 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * $FreeBSD: src/sys/dev/ata/ata-queue.c,v 1.65 2006/07/21 19:13:05 imp Exp $
- * $DragonFly: src/sys/dev/disk/nata/ata-queue.c,v 1.5 2007/06/01 00:31:15 dillon Exp $
+ * $DragonFly: src/sys/dev/disk/nata/ata-queue.c,v 1.6 2007/06/03 11:52:09 dillon Exp $
  */
 
 #include "opt_ata.h"
@@ -77,6 +77,8 @@ ata_queue_request(struct ata_request *request)
 	    spin_unlock_wr(&ch->state_mtx);
 	    return;
 	}
+	/* interlock against interrupt */
+	request->flags |= ATA_R_HWCMDQUEUED;
 	spin_unlock_wr(&ch->state_mtx);
     }
     /* otherwise put request on the locked queue at the specified location */
@@ -218,6 +220,10 @@ ata_start(device_t dev)
 		    ata_finish(request);
 		    return;
 		}
+
+		/* interlock against interrupt */
+		request->flags |= ATA_R_HWCMDQUEUED;
+
 		if (dumping) {
 		    spin_unlock_wr(&ch->state_mtx);
 		    spin_unlock_wr(&ch->queue_mtx);
-- 
2.11.4.GIT