linux-kernel - [PATCH] drm/msm/gem: Drop early returns in close/purge vma

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Message-Id: <20220610172055.2337977-1-robdclark@gmail.com>
Date:   Fri, 10 Jun 2022 10:20:55 -0700
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     freedreno@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        Rob Clark <robdclark@...omium.org>,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] drm/msm/gem: Drop early returns in close/purge vma

From: Rob Clark <robdclark@...omium.org>

Keep the warn, but drop the early return.  If we do manage to hit this
sort of issue, skipping the cleanup just makes things worse (dangling
drm_mm_nodes when the msm_gem_vma is freed, etc).  Whereas the worst
that happens if we tear down a mapping the GPU is accessing is that we
get GPU iova faults, but otherwise the world keeps spinning.

Signed-off-by: Rob Clark <robdclark@...omium.org>
---
 drivers/gpu/drm/msm/msm_gem_vma.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c b/drivers/gpu/drm/msm/msm_gem_vma.c
index 3c1dc9241831..c471aebcdbab 100644
--- a/drivers/gpu/drm/msm/msm_gem_vma.c
+++ b/drivers/gpu/drm/msm/msm_gem_vma.c
@@ -62,8 +62,7 @@ void msm_gem_purge_vma(struct msm_gem_address_space *aspace,
 	unsigned size = vma->node.size;
 
 	/* Print a message if we try to purge a vma in use */
-	if (GEM_WARN_ON(msm_gem_vma_inuse(vma)))
-		return;
+	GEM_WARN_ON(msm_gem_vma_inuse(vma));
 
 	/* Don't do anything if the memory isn't mapped */
 	if (!vma->mapped)
@@ -128,8 +127,7 @@ msm_gem_map_vma(struct msm_gem_address_space *aspace,
 void msm_gem_close_vma(struct msm_gem_address_space *aspace,
 		struct msm_gem_vma *vma)
 {
-	if (GEM_WARN_ON(msm_gem_vma_inuse(vma) || vma->mapped))
-		return;
+	GEM_WARN_ON(msm_gem_vma_inuse(vma) || vma->mapped);
 
 	spin_lock(&aspace->lock);
 	if (vma->iova)
-- 
2.36.1