diff options
| author | Rob Herring <robh@kernel.org> | 2019-08-22 21:12:14 -0500 |
|---|---|---|
| committer | Rob Herring <robh@kernel.org> | 2019-08-28 10:02:39 -0500 |
| commit | 55b9a0549e4303ca43481f9ba2cdfa305277d97d (patch) | |
| tree | b8520f2a5fd14c1508588c1501ce0cb591d9fc38 | |
| parent | edbd7f318cd66cec4588a28ba6985b014456dbca (diff) | |
drm/panfrost: Use mutex_trylock in panfrost_gem_purge
Lockdep reports a circular locking dependency with pages_lock taken in
the shrinker callback. The deadlock can't actually happen with current
users at least as a BO will never be purgeable when pages_lock is held.
To be safe, let's use mutex_trylock() instead and bail if a BO is locked
already.
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190823021216.5862-7-robh@kernel.org
| -rw-r--r-- | drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c index d191632b6197..458f0fa68111 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c @@ -36,15 +36,18 @@ panfrost_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc return count; } -static void panfrost_gem_purge(struct drm_gem_object *obj) +static bool panfrost_gem_purge(struct drm_gem_object *obj) { struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); - mutex_lock(&shmem->pages_lock); + + if (!mutex_trylock(&shmem->pages_lock)) + return false; panfrost_mmu_unmap(to_panfrost_bo(obj)); drm_gem_shmem_purge_locked(obj); mutex_unlock(&shmem->pages_lock); + return true; } static unsigned long @@ -61,8 +64,8 @@ panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) { if (freed >= sc->nr_to_scan) break; - if (drm_gem_shmem_is_purgeable(shmem)) { - panfrost_gem_purge(&shmem->base); + if (drm_gem_shmem_is_purgeable(shmem) && + panfrost_gem_purge(&shmem->base)) { freed += shmem->base.size >> PAGE_SHIFT; list_del_init(&shmem->madv_list); } |