Userspace might tag a BO purgeable while it's still referenced by GPU
jobs. We need to make sure the shrinker does not purge such BOs until
all jobs referencing it are finished.
Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
---
drivers/gpu/drm/panfrost/panfrost_drv.c | 1 +
drivers/gpu/drm/panfrost/panfrost_gem.h | 6 ++++++
drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c | 2 ++
drivers/gpu/drm/panfrost/panfrost_job.c | 7 ++++++-
4 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index b406b5243b40..297c0e7304d2 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -166,6 +166,7 @@ panfrost_lookup_bos(struct drm_device *dev,
break;
}
+ atomic_inc(&bo->gpu_usecount);
job->mappings[i] = mapping;
}
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h
index ca1bc9019600..b3517ff9630c 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.h
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
@@ -30,6 +30,12 @@ struct panfrost_gem_object {
struct mutex lock;
} mappings;
+ /*
+ * Count the number of jobs referencing this BO so we don't let the
+ * shrinker reclaim this object prematurely.
+ */
+ atomic_t gpu_usecount;
+
bool noexec :1;
bool is_heap :1;
};
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
index b36df326c860..288e46c40673 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
@@ -41,6 +41,8 @@ static bool panfrost_gem_purge(struct drm_gem_object *obj)
struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
struct panfrost_gem_object *bo = to_panfrost_bo(obj);
+ if (atomic_read(&bo->gpu_usecount))
+ return false;
if (!mutex_trylock(&shmem->pages_lock))
return false;
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index c85d45be3b5e..2b12aa87ff32 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -270,8 +270,13 @@ static void panfrost_job_cleanup(struct kref *ref)
dma_fence_put(job->render_done_fence);
if (job->mappings) {
- for (i = 0; i < job->bo_count; i++)
+ for (i = 0; i < job->bo_count; i++) {
+ if (!job->mappings[i])
+ break;
+
+ atomic_dec(&job->mappings[i]->obj->gpu_usecount);
panfrost_gem_mapping_put(job->mappings[i]);
+ }
kvfree(job->mappings);
}
--
2.23.0
