linux-kernel - [PATCH] drm/hyperv: Don't overwrite dirt

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Date:   Mon, 12 Sep 2022 08:32:46 -0700
From:   Saurabh Sengar <ssengar@...ux.microsoft.com>
To:     ssengar@...rosoft.com, drawat.floss@...il.com, airlied@...ux.ie,
        daniel@...ll.ch, linux-hyperv@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        mikelley@...rosoft.com
Subject: [PATCH] drm/hyperv: Don't overwrite dirt_needed value set by host

Existing code is causing a race condition where dirt_needed value is
already set by the host and gets overwritten with default value. Remove
this default setting of dirt_needed, to avoid overwriting the value
received in the channel callback set by vmbus_open. Removing this
setting also means the default value for dirt_needed is changed to false
as it's allocated by kzalloc which is similar to legacy hyperv_fb driver.

Signed-off-by: Saurabh Sengar <ssengar@...ux.microsoft.com>
---
 drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
index 4a8941fa0815..57d49a08b37f 100644
--- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
+++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
@@ -198,8 +198,6 @@ static int hyperv_vmbus_probe(struct hv_device *hdev,
 	if (ret)
 		drm_warn(dev, "Failed to update vram location.\n");
 
-	hv->dirt_needed = true;
-
 	ret = hyperv_mode_config_init(hv);
 	if (ret)
 		goto err_vmbus_close;
-- 
2.31.1