[PATCH] i915: don't call drm_atomic_state_put on invalid pointer

From: Arnd Bergmann
Date: Tue Oct 18 2016 - 11:17:31 EST

The introduction of reference counting on the state structures caused
sanitize_watermarks() in i915 to break in the error handling case,
as pointed out by gcc -Wmaybe-uninitialized

drivers/gpu/drm/i915/intel_display.c: In function âintel_modeset_initâ:
include/drm/drm_atomic.h:224:2: error: âstateâ may be used uninitialized in this function [-Werror=maybe-uninitialized]

This changes the function back to only drop the reference count
when it was successfully allocated first.

Fixes: 0853695c3ba4 ("drm: Add reference counting to drm_atomic_state")
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
drivers/gpu/drm/i915/intel_display.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 6d168685bbda..6a26da143aa6 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -16314,7 +16314,7 @@ static void sanitize_watermarks(struct drm_device *dev)
* BIOS-programmed watermarks untouched and hope for the best.
WARN(true, "Could not determine valid watermarks for inherited state\n");
- goto fail;
+ goto put_state;

/* Write calculated watermark values back */
@@ -16325,8 +16325,9 @@ static void sanitize_watermarks(struct drm_device *dev)