[PATCH 4/4] gntdev: Unchecked finction result

[Andrey Shumilin]

The dma_coerce_mask_and_coherent function may refuse
to apply a mask due to incorrectly passed parameters.
But since this function returns the error -EIO, this
is an abnormal situation and the error must be written to the log.

Signed-off-by: Andrey Shumilin <shum.sdl@xxxxxxxx>
Found by Linux Verification Center (linuxtesting.org) with SVACE.
---
 drivers/xen/gntdev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 61faea1f0663..8a448dbbca86 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -597,7 +597,8 @@ static int gntdev_open(struct inode *inode, struct file *flip)
 	flip->private_data = priv;
 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
 	priv->dma_dev = gntdev_miscdev.this_device;
-	dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));
+	if (dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64)) == -EIO)
+		printk(KERN_INFO "The mask was applied unsuccessfully");
 #endif
 	pr_debug("priv %p\n", priv);
 
-- 
2.30.2