linux-kernel - Re: [PATCH v3 2/4] drm/qxl: unpin release objects

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Message-ID: <20210125121619.7w3flilhe5juiuyf@sirius.home.kraxel.org>
Date:   Mon, 25 Jan 2021 13:16:19 +0100
From:   Gerd Hoffmann <kraxel@...hat.com>
To:     Daniel Vetter <daniel@...ll.ch>
Cc:     Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        open list <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        "open list:DRM DRIVER FOR QXL VIRTUAL GPU" 
        <virtualization@...ts.linux-foundation.org>,
        Dave Airlie <airlied@...hat.com>,
        "open list:DRM DRIVER FOR QXL VIRTUAL GPU" 
        <spice-devel@...ts.freedesktop.org>
Subject: Re: [PATCH v3 2/4] drm/qxl: unpin release objects

> > Just calling ttm_bo_unpin() here makes lockdep unhappy.
> 
> How does that one splat? But yeah if that's a problem should be
> explained in the comment. I'd then also only do a pin_count--; to make
> sure you can still catch other pin leaks if you have them. Setting it
> to 0 kinda defeats the warning.

Figured the unpin is at the completely wrong place while trying to
reproduce the lockdep splat ...

take care,
  Gerd

>From 43befab4a935114e8620af62781666fa81288255 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@...hat.com>
Date: Mon, 25 Jan 2021 13:10:50 +0100
Subject: [PATCH] drm/qxl: unpin release objects

Balances the qxl_create_bo(..., pinned=true, ...);
call in qxl_release_bo_alloc().

Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>
---
 drivers/gpu/drm/qxl/qxl_release.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index c52412724c26..28013fd1f8ea 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -347,6 +347,7 @@ int qxl_alloc_release_reserved(struct qxl_device *qdev, unsigned long size,
 
 	mutex_lock(&qdev->release_mutex);
 	if (qdev->current_release_bo_offset[cur_idx] + 1 >= releases_per_bo[cur_idx]) {
+		qxl_bo_unpin(qdev->current_release_bo[cur_idx]);
 		qxl_bo_unref(&qdev->current_release_bo[cur_idx]);
 		qdev->current_release_bo_offset[cur_idx] = 0;
 		qdev->current_release_bo[cur_idx] = NULL;
-- 
2.29.2