[PATCH 3.10 10/43] spi: dw-mid: check that DMA was inited before exit

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

commit fb57862ead652454ceeb659617404c5f13bc34b5 upstream.

If the driver was compiled with DMA support, but DMA channels weren't acquired
by some reason, mid_spi_dma_exit() will crash the kernel.

Fixes: 7063c0d942a1 (spi/dw_spi: add DMA support)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/spi/spi-dw-mid.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -89,6 +89,8 @@ err_exit:
 
 static void mid_spi_dma_exit(struct dw_spi *dws)
 {
+	if (!dws->dma_inited)
+		return;
 	dma_release_channel(dws->txchan);
 	dma_release_channel(dws->rxchan);
 }