diff --git a/drivers/dma/idma64.c b/drivers/dma/idma64.c
index 40dc5d2ddf3d..0baf9797cc09 100644
--- a/drivers/dma/idma64.c
+++ b/drivers/dma/idma64.c
@@ -142,9 +142,8 @@ static void idma64_chan_irq(struct idma64 *idma64, unsigned short c,
 {
 	struct idma64_chan *idma64c = &idma64->chan[c];
 	struct idma64_desc *desc;
-	unsigned long flags;
 
-	spin_lock_irqsave(&idma64c->vchan.lock, flags);
+	spin_lock(&idma64c->vchan.lock);
 	desc = idma64c->desc;
 	if (desc) {
 		if (status_err & (1 << c)) {
@@ -161,7 +160,7 @@ static void idma64_chan_irq(struct idma64 *idma64, unsigned short c,
 		if (idma64c->desc == NULL || desc->status == DMA_ERROR)
 			idma64_stop_transfer(idma64c);
 	}
-	spin_unlock_irqrestore(&idma64c->vchan.lock, flags);
+	spin_unlock(&idma64c->vchan.lock);
 }
 
 static irqreturn_t idma64_irq(int irq, void *dev)
diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c
index 4fa4c06c9edb..0fec3c554fe3 100644
--- a/drivers/dma/ioat/init.c
+++ b/drivers/dma/ioat/init.c
@@ -129,7 +129,7 @@ static void
 ioat_init_channel(struct ioatdma_device *ioat_dma,
 		  struct ioatdma_chan *ioat_chan, int idx);
 static void ioat_intr_quirk(struct ioatdma_device *ioat_dma);
-static int ioat_enumerate_channels(struct ioatdma_device *ioat_dma);
+static void ioat_enumerate_channels(struct ioatdma_device *ioat_dma);
 static int ioat3_dma_self_test(struct ioatdma_device *ioat_dma);
 
 static int ioat_dca_enabled = 1;
@@ -575,7 +575,7 @@ static void ioat_dma_remove(struct ioatdma_device *ioat_dma)
  * ioat_enumerate_channels - find and initialize the device's channels
  * @ioat_dma: the ioat dma device to be enumerated
  */
-static int ioat_enumerate_channels(struct ioatdma_device *ioat_dma)
+static void ioat_enumerate_channels(struct ioatdma_device *ioat_dma)
 {
 	struct ioatdma_chan *ioat_chan;
 	struct device *dev = &ioat_dma->pdev->dev;
@@ -594,7 +594,7 @@ static int ioat_enumerate_channels(struct ioatdma_device *ioat_dma)
 	xfercap_log = readb(ioat_dma->reg_base + IOAT_XFERCAP_OFFSET);
 	xfercap_log &= 0x1f; /* bits [4:0] valid */
 	if (xfercap_log == 0)
-		return 0;
+		return;
 	dev_dbg(dev, "%s: xfercap = %d\n", __func__, 1 << xfercap_log);
 
 	for (i = 0; i < dma->chancnt; i++) {
@@ -611,7 +611,6 @@ static int ioat_enumerate_channels(struct ioatdma_device *ioat_dma)
 		}
 	}
 	dma->chancnt = i;
-	return i;
 }
 
 /**
@@ -1205,8 +1204,15 @@ static void ioat_shutdown(struct pci_dev *pdev)
 
 		spin_lock_bh(&ioat_chan->prep_lock);
 		set_bit(IOAT_CHAN_DOWN, &ioat_chan->state);
-		del_timer_sync(&ioat_chan->timer);
 		spin_unlock_bh(&ioat_chan->prep_lock);
+		/*
+		 * Synchronization rule for del_timer_sync():
+		 *  - The caller must not hold locks which would prevent
+		 *    completion of the timer's handler.
+		 * So prep_lock cannot be held before calling it.
+		 */
+		del_timer_sync(&ioat_chan->timer);
+
 		/* this should quiesce then reset */
 		ioat_reset_hw(ioat_chan);
 	}