[PATCH] libata: fix ata_dma_enabled

[Aaron Lu <aaron.lu@intel.com>]

ata_dma_enabled should check if device is either using multi word DMA
or ultra DMA instead of checking 0xff, as dma_mode 0 is not a valid dma
mode either.

This patch fixes the following bug:
https://bugzilla.kernel.org/show_bug.cgi?id=49151

Reported-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Tested-by: Dutra Julio <dutra.julio@gmail.com>
Tested-by: Szymon Janc <szymon@janc.net.pl>
Tested-by: Bernd Buschinski <b.buschinski@googlemail.com>
Cc: <stable@kernel.org>
---
 include/linux/libata.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 77eeeda..2444695 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1617,7 +1617,7 @@ static inline int ata_using_udma(struct ata_device *adev)
 
 static inline int ata_dma_enabled(struct ata_device *adev)
 {
-	return (adev->dma_mode == 0xFF ? 0 : 1);
+	return ata_using_mwdma(adev) || ata_using_udma(adev);
 }
 
 /**************************************************************************
-- 
1.8.0.1.2.gd1eded4