[v1] gpu: drm: sti: sti_vtac:- Handle return NULL error from devm_ioremap_nocache

[Arvind Yadav]

Here, If devm_ioremap_nocache will fail. It will return NULL.
Kernel can run into a NULL-pointer dereference. This error check
will avoid NULL pointer dereference.

Signed-off-by: Arvind Yadav <arvind.yadav.cs at gmail.com>
---
 drivers/gpu/drm/sti/sti_vtac.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/sti/sti_vtac.c b/drivers/gpu/drm/sti/sti_vtac.c
index cf7fe8a..dd749e9 100644
--- a/drivers/gpu/drm/sti/sti_vtac.c
+++ b/drivers/gpu/drm/sti/sti_vtac.c
@@ -191,6 +191,10 @@ static int sti_vtac_probe(struct platform_device *pdev)
 	if (res) {
 		vtac->phy_regs = devm_ioremap_nocache(dev, res->start,
 						 resource_size(res));
+			if (!vtac->phy_regs) {
+				DRM_ERROR("failed to remap I/O memory\n");
+				return -ENOMEM;
+			}
 		sti_vtac_tx_set_config(vtac);
 	} else {
 
-- 
1.7.9.5