From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Cc: Matthew Auld <matthew.auld@intel.com>,
stable@vger.kernel.org, Chris Wilson <chris@chris-wilson.co.uk>
Subject: [Intel-gfx] [PATCH] drm/i915: Always flush the active worker before returning from the wait
Date: Thu, 21 Jan 2021 23:28:07 +0000 [thread overview]
Message-ID: <20210121232807.16618-1-chris@chris-wilson.co.uk> (raw)
The first thing the active retirement worker does is decrement the
i915_active count.
The first thing we do during i915_active_wait is try to increment the
i915_active count, but only if already active [non-zero].
The wait may see that the retirement is already started and so marked the
i915_active as idle, and skip waiting for the retirement handler.
However, the caller of i915_active_wait may immediately free the
i915_active upon returning (e.g. i915_vma_destroy) so we must not return
before the concurrent access from the worker are completed. We must
always flush the worker.
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2473
Fixes: 274cbf20fd10 ("drm/i915: Push the i915_active.retire into a worker")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
---
drivers/gpu/drm/i915/i915_active.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index ab4382841c6b..3bc616cc1ad2 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -628,24 +628,26 @@ static int flush_lazy_signals(struct i915_active *ref)
int __i915_active_wait(struct i915_active *ref, int state)
{
- int err;
-
might_sleep();
- if (!i915_active_acquire_if_busy(ref))
- return 0;
-
/* Any fence added after the wait begins will not be auto-signaled */
- err = flush_lazy_signals(ref);
- i915_active_release(ref);
- if (err)
- return err;
+ if (i915_active_acquire_if_busy(ref)) {
+ int err;
- if (!i915_active_is_idle(ref) &&
- ___wait_var_event(ref, i915_active_is_idle(ref),
- state, 0, 0, schedule()))
- return -EINTR;
+ err = flush_lazy_signals(ref);
+ i915_active_release(ref);
+ if (err)
+ return err;
+ if (___wait_var_event(ref, i915_active_is_idle(ref),
+ state, 0, 0, schedule()))
+ return -EINTR;
+ }
+
+ /*
+ * After the wait is complete, the caller may free the active.
+ * We have to flush any concurrent retirement before returning.
+ */
flush_work(&ref->work);
return 0;
}
--
2.20.1
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next reply other threads:[~2021-01-21 23:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 23:28 Chris Wilson [this message]
2021-01-22 5:00 ` [Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915: Always flush the active worker before returning from the wait Patchwork
2021-01-22 9:03 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2021-01-22 10:27 ` [Intel-gfx] [PATCH] " Matthew Auld
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