mmc: tmio: always unmap DMA before waiting for interrupt

Wolfram Sang · storulf · commit 5f07ef8f603a · 2017-04-24T21:41:40.000+02:00
In the (maybe academical) case, we don't get a DATAEND interrupt after
DMA completed, we will wait endlessly for the completion to complete.
This is not bad per se, since we have a more generic completion tracking
a timeout. In that rare case, however, the DMA buffer will not get
unmapped and we have a leak. Reorder the code, so unmapping will always
take place.

Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Signed-off-by: Ulf Hansson &lt;ulf.hansson@linaro.org&gt;
diff --git a/drivers/mmc/host/tmio_mmc_dma.c b/drivers/mmc/host/tmio_mmc_dma.c
@@ -47,8 +47,6 @@ static void tmio_mmc_dma_callback(void *arg)
 {
 	struct tmio_mmc_host *host = arg;
 
-	wait_for_completion(&host->dma_dataend);
-
 	spin_lock_irq(&host->lock);
 
 	if (!host->data)
@@ -63,6 +61,11 @@ static void tmio_mmc_dma_callback(void *arg)
 			     host->sg_ptr, host->sg_len,
 			     DMA_TO_DEVICE);
 
+	spin_unlock_irq(&host->lock);
+
+	wait_for_completion(&host->dma_dataend);
+
+	spin_lock_irq(&host->lock);
 	tmio_mmc_do_data_irq(host);
 out:
 	spin_unlock_irq(&host->lock);
