For locking semantics it really doesn't matter when we grab the ticket. But for lockdep validation it does: the acquire ctx is a fake lockdep. Since other drivers might want to do a full multi-lock dance in their fault-handler, not just lock a single dma_resv. Therefore we must init the acquire_ctx only after we've done all the copy_*_user or anything else that might trigger a pagefault. For msm this means we need to move it past submit_lookup_objects. Aside: Why is msm still using struct_mutex, it seems to be using dma_resv_lock for general buffer state protection? v2: - Add comment to explain why the ww ticket setup is separate (Rob) - Fix up error handling, we need to make sure we don't call ww_acquire_fini without _init. Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx> Cc: Rob Clark <robdclark@xxxxxxxxx> Cc: Sean Paul <sean@xxxxxxxxxx> Cc: linux-arm-msm@xxxxxxxxxxxxxxx Cc: freedreno@xxxxxxxxxxxxxxxxxxxxx --- drivers/gpu/drm/msm/msm_gem_submit.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c index fb1fdd7fa3ef..385d4965a8d0 100644 --- a/drivers/gpu/drm/msm/msm_gem_submit.c +++ b/drivers/gpu/drm/msm/msm_gem_submit.c @@ -54,7 +54,6 @@ static struct msm_gem_submit *submit_create(struct drm_device *dev, INIT_LIST_HEAD(&submit->node); INIT_LIST_HEAD(&submit->bo_list); - ww_acquire_init(&submit->ticket, &reservation_ww_class); return submit; } @@ -390,8 +389,6 @@ static void submit_cleanup(struct msm_gem_submit *submit) list_del_init(&msm_obj->submit_entry); drm_gem_object_put(&msm_obj->base); } - - ww_acquire_fini(&submit->ticket); } int msm_ioctl_gem_submit(struct drm_device *dev, void *data, @@ -408,6 +405,7 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, struct msm_ringbuffer *ring; int out_fence_fd = -1; struct pid *pid = get_pid(task_pid(current)); + bool has_ww_ticket = false; unsigned i; int ret, submitid; if (!gpu) @@ -489,6 +487,9 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, if (ret) goto out; + /* copy_*_user while holding a ww ticket upsets lockdep */ + ww_acquire_init(&submit->ticket, &reservation_ww_class); + has_ww_ticket = true; ret = submit_lock_objects(submit); if (ret) goto out; @@ -588,6 +589,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, out: submit_cleanup(submit); + if (has_ww_ticket) + ww_acquire_fini(&submit->ticket); if (ret) msm_gem_submit_free(submit); out_unlock: -- 2.24.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
