[PATCH 5.14 075/172] drm/i915/gvt: fix the usage of ww lock in gvt scheduler.

Greg Kroah-Hartman
2021-10-04T13:33:56Z

From: Zhi A Wang <zhi.wang.linux2@gmail.com>

[ Upstream commit d168cd797982db9db617113644c87b8f5f3cf27e ]

As the APIs related to ww lock in i915 was changed recently, the usage of
ww lock in GVT-g scheduler needs to be changed accrodingly. We noticed a
deadlock when GVT-g scheduler submits the workload to i915. After some
investigation, it seems the way of how to use ww lock APIs has been
changed. Releasing a ww now requires a explicit i915_gem_ww_ctx_fini().

Fixes: 67f1120381df ("drm/i915/gvt: Introduce per object locking in GVT scheduler.")
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Zhi A Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20210826143834.25410-1-zhi.a.wang@intel.com
Acked-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/i915/gvt/scheduler.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index 734c37c5e347..527b59b86312 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -576,7 +576,7 @@ static int prepare_shadow_batch_buffer(struct intel_vgpu_workload *workload)

/* No one is going to touch shadow bb from now on. */
i915_gem_object_flush_map(bb->obj);
- i915_gem_object_unlock(bb->obj);
+ i915_gem_ww_ctx_fini(&ww);
}
}
return 0;
@@ -630,7 +630,7 @@ static int prepare_shadow_wa_ctx(struct intel_shadow_wa_ctx *wa_ctx)
return ret;
}

- i915_gem_object_unlock(wa_ctx->indirect_ctx.obj);
+ i915_gem_ww_ctx_fini(&ww);

/* FIXME: we are not tracking our pinned VMA leaving it
* up to the core to fix up the stray pin_count upon
--
2.33.0