Properly protect all accesses to maple_waitq or maple_sentq with
maple_wlist_lock.  

Signed-off-by: Jörn Engel <joern@logfs.org>
---

 drivers/sh/maple/maple.c |   31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)


--- maple/drivers/sh/maple/maple.c~cu7	2008-03-24 17:49:59.000000000 +0100
+++ maple/drivers/sh/maple/maple.c	2008-03-24 18:02:03.000000000 +0100
@@ -236,17 +236,13 @@ static void maple_send(void)
 	int maple_packets;
 	struct mapleq *mq, *nmq;
 
-	if (!list_empty(&maple_sentq))
-		return;
 	mutex_lock(&maple_wlist_lock);
-	if (list_empty(&maple_waitq) || !maple_dma_done()) {
-		mutex_unlock(&maple_wlist_lock);
-		return;
-	}
-	mutex_unlock(&maple_wlist_lock);
+	if (!list_empty(&maple_sentq))
+		goto out;
+	if (list_empty(&maple_waitq) || !maple_dma_done())
+		goto out;
 	maple_packets = 0;
 	maple_sendptr = maple_lastptr = maple_sendbuf;
-	mutex_lock(&maple_wlist_lock);
 	list_for_each_entry_safe(mq, nmq, &maple_waitq, list) {
 		maple_build_block(mq);
 		list_move(&mq->list, &maple_sentq);
@@ -259,6 +255,9 @@ static void maple_send(void)
 			dma_cache_sync(0, maple_sendbuf + i * PAGE_SIZE,
 				       PAGE_SIZE, DMA_BIDIRECTIONAL);
 	}
+	return;
+out:
+	mutex_unlock(&maple_wlist_lock);
 }
 
 /* check if there is a driver registered likely to match this device */
@@ -401,24 +400,22 @@ setup_finished:
 /* VBLANK bottom half - implemented via workqueue */
 static void maple_vblank_handler(struct work_struct *work)
 {
+	mutex_lock(&maple_wlist_lock);
 	if (!list_empty(&maple_sentq))
-		return;
+		goto out;
 	if (!maple_dma_done())
-		return;
+		goto out;
 	ctrl_outl(0, MAPLE_ENABLE);
 	bus_for_each_dev(&maple_bus_type, NULL, NULL,
 			 setup_maple_commands);
 	if (time_after(jiffies, maple_pnp_time))
 		maple_pnp_time = jiffies + MAPLE_PNP_INTERVAL;
-	mutex_lock(&maple_wlist_lock);
-	if (!list_empty(&maple_waitq) && list_empty(&maple_sentq)) {
-		mutex_unlock(&maple_wlist_lock);
+	if (!list_empty(&maple_waitq) && list_empty(&maple_sentq))
 		maple_send();
-	} else {
-		mutex_unlock(&maple_wlist_lock);
-	}
 
 	maplebus_dma_reset();
+out:
+	mutex_unlock(&maple_wlist_lock);
 }
 
 /* handle devices added via hotplugs - placing them on queue for DEVINFO*/
@@ -540,6 +537,7 @@ static void maple_dma_handler(struct wor
 	if (!maple_dma_done())
 		return;
 	ctrl_outl(0, MAPLE_ENABLE);
+	mutex_lock(&maple_wlist_lock);
 	if (!list_empty(&maple_sentq)) {
 		list_for_each_entry_safe(mq, nmq, &maple_sentq, list) {
 			recvbuf = mq->recvbuf;
@@ -595,6 +593,7 @@ static void maple_dma_handler(struct wor
 		if (started == 0)
 			started = 1;
 	}
+	mutex_unlock(&maple_wlist_lock);
 	maplebus_dma_reset();
 }