[PATCH 4.19 090/103] drm/nouveau/bar/gf100: ensure BAR is mapped

[Greg Kroah-Hartman]

From: Jon Derrick <jonathan.derrick@xxxxxxxxx>

commit 12e08beb32d64b6070b718630490db83dd321c8c upstream.

If the BAR is zero size, it indicates it was never successfully mapped.
Ensure that the BAR is valid during initialization before attempting to
use it.

Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
Signed-off-by: Sushma Kalakota <sushmax.kalakota@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c
@@ -94,6 +94,8 @@ gf100_bar_oneinit_bar(struct gf100_bar *
 		return ret;
 
 	bar_len = device->func->resource_size(device, bar_nr);
+	if (!bar_len)
+		return -ENOMEM;
 	if (bar_nr == 3 && bar->bar2_halve)
 		bar_len >>= 1;