[PATCH 01/11] drm/i915/gt: Close race between engine_park and intel_gt_retire_requests
Chris Wilson
chris at chris-wilson.co.uk
Sat Nov 16 17:21:46 UTC 2019
Fixes: e5dadff4b093 ("drm/i915: Protect request retirement with timeline->mutex")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld at intel.com>
---
drivers/gpu/drm/i915/gt/intel_gt_requests.c | 8 ++++----
drivers/gpu/drm/i915/gt/intel_timeline.c | 14 ++++++++------
drivers/gpu/drm/i915/gt/intel_timeline_types.h | 2 +-
3 files changed, 13 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
index a79e6efb31a2..7559d6373f49 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
@@ -49,8 +49,8 @@ long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout)
continue;
intel_timeline_get(tl);
- GEM_BUG_ON(!tl->active_count);
- tl->active_count++; /* pin the list element */
+ GEM_BUG_ON(!atomic_read(&tl->active_count));
+ atomic_inc(&tl->active_count); /* pin the list element */
spin_unlock_irqrestore(&timelines->lock, flags);
if (timeout > 0) {
@@ -71,14 +71,14 @@ long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout)
/* Resume iteration after dropping lock */
list_safe_reset_next(tl, tn, link);
- if (!--tl->active_count)
+ if (atomic_dec_and_test(&tl->active_count))
list_del(&tl->link);
mutex_unlock(&tl->mutex);
/* Defer the final release to after the spinlock */
if (refcount_dec_and_test(&tl->kref.refcount)) {
- GEM_BUG_ON(tl->active_count);
+ GEM_BUG_ON(atomic_read(&tl->active_count));
list_add(&tl->link, &free);
}
}
diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c b/drivers/gpu/drm/i915/gt/intel_timeline.c
index 16a9e88d93de..313552e88318 100644
--- a/drivers/gpu/drm/i915/gt/intel_timeline.c
+++ b/drivers/gpu/drm/i915/gt/intel_timeline.c
@@ -337,12 +337,13 @@ void intel_timeline_enter(struct intel_timeline *tl)
lockdep_assert_held(&tl->mutex);
GEM_BUG_ON(!atomic_read(&tl->pin_count));
- if (tl->active_count++)
+ if (atomic_add_unless(&tl->active_count, 1, 0))
return;
- GEM_BUG_ON(!tl->active_count); /* overflow? */
+ GEM_BUG_ON(!atomic_read(&tl->pin_count)); /* overflow? */
spin_lock_irqsave(&timelines->lock, flags);
- list_add(&tl->link, &timelines->active_list);
+ if (!atomic_fetch_inc(&tl->active_count))
+ list_add(&tl->link, &timelines->active_list);
spin_unlock_irqrestore(&timelines->lock, flags);
}
@@ -353,12 +354,13 @@ void intel_timeline_exit(struct intel_timeline *tl)
lockdep_assert_held(&tl->mutex);
- GEM_BUG_ON(!tl->active_count);
- if (--tl->active_count)
+ GEM_BUG_ON(!atomic_read(&tl->active_count));
+ if (atomic_add_unless(&tl->active_count, -1, 1))
return;
spin_lock_irqsave(&timelines->lock, flags);
- list_del(&tl->link);
+ if (atomic_dec_and_test(&tl->active_count))
+ list_del(&tl->link);
spin_unlock_irqrestore(&timelines->lock, flags);
/*
diff --git a/drivers/gpu/drm/i915/gt/intel_timeline_types.h b/drivers/gpu/drm/i915/gt/intel_timeline_types.h
index 98d9ee166379..5244615ed1cb 100644
--- a/drivers/gpu/drm/i915/gt/intel_timeline_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_timeline_types.h
@@ -42,7 +42,7 @@ struct intel_timeline {
* from the intel_context caller plus internal atomicity.
*/
atomic_t pin_count;
- unsigned int active_count;
+ atomic_t active_count;
const u32 *hwsp_seqno;
struct i915_vma *hwsp_ggtt;
--
2.24.0
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