[PATCH 4.18 155/197] drm/i915: Free write_buf that we allocated with kzalloc.

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>

commit 1b1b1162745e5f9e5c6c095afc8081df3edabc50 upstream.

We use kzalloc to allocate the write_buf that we use for
i2c transfer on hdcp write. But it seems that we are forgetting
to free the memory that is not needed after i2c transfer is
completed.

Reported-by: Brian J Wood <brian.j.wood@xxxxxxxxx>
Fixes: 2320175feb74 ("drm/i915: Implement HDCP for HDMI")
Cc: Ramalingam C <ramalingam.c@xxxxxxxxx>
Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.17+
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20180823205136.31310-1-rodrigo.vivi@xxxxxxxxx
(cherry picked from commit 62d3a8deaa10b8346d979d0dabde56c33b742afa)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/i915/intel_hdmi.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -933,8 +933,12 @@ static int intel_hdmi_hdcp_write(struct
 
 	ret = i2c_transfer(adapter, &msg, 1);
 	if (ret == 1)
-		return 0;
-	return ret >= 0 ? -EIO : ret;
+		ret = 0;
+	else if (ret >= 0)
+		ret = -EIO;
+
+	kfree(write_buf);
+	return ret;
 }
 
 static