[Intel-gfx] [PATCH] drm/i915: Remove nest annotation from intel_context_unpin

[Maarten Lankhorst]

Lets see what breaks, round 3?

Signed-off-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
---
 drivers/gpu/drm/i915/gt/intel_context.c       | 27 +++++++++++++------
 drivers/gpu/drm/i915/gt/intel_context_types.h |  1 +
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_context.c 
b/drivers/gpu/drm/i915/gt/intel_context.c
index fbaa9df6f436..671049695e6b 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.c
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -47,21 +47,30 @@ int __intel_context_do_pin(struct intel_context *ce)
 {
        int err;
 
-       if (mutex_lock_interruptible(&ce->pin_mutex))
-               return -EINTR;
-
-       if (likely(!atomic_read(&ce->pin_count))) {
-               intel_wakeref_t wakeref;
+       if (unlikely(!test_bit(CONTEXT_ALLOC_BIT, &ce->flags))) {
+               err = mutex_lock_interruptible(&ce->alloc_mutex);
+               if (err)
+                       return err;
 
-               if (unlikely(!test_bit(CONTEXT_ALLOC_BIT, &ce->flags))) {
+               if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
                        err = ce->ops->alloc(ce);
                        if (unlikely(err))
                                goto err;
 
+                       smp_mb(); /* Make sure allocation is flushed to memory 
*/
+
                        __set_bit(CONTEXT_ALLOC_BIT, &ce->flags);
                }
+               mutex_unlock(&ce->alloc_mutex);
+       }
+
+       err = mutex_lock_interruptible(&ce->pin_mutex);
+       if (err)
+               return err;
+
+       if (likely(!atomic_read(&ce->pin_count))) {
+               intel_wakeref_t wakeref;
 
-               err = 0;
                with_intel_runtime_pm(ce->engine->uncore->rpm, wakeref)
                        err = ce->ops->pin(ce);
                if (err)
@@ -91,7 +100,7 @@ void intel_context_unpin(struct intel_context *ce)
 
        /* We may be called from inside intel_context_pin() to evict another */
        intel_context_get(ce);
-       mutex_lock_nested(&ce->pin_mutex, SINGLE_DEPTH_NESTING);
+       mutex_lock(&ce->pin_mutex);
 
        if (likely(atomic_dec_and_test(&ce->pin_count))) {
                CE_TRACE(ce, "retire\n");
@@ -228,6 +237,7 @@ intel_context_init(struct intel_context *ce,
        INIT_LIST_HEAD(&ce->signals);
 
        mutex_init(&ce->pin_mutex);
+       mutex_init(&ce->alloc_mutex);
 
        i915_active_init(&ce->active,
                         __intel_context_active, __intel_context_retire);
@@ -239,6 +249,7 @@ void intel_context_fini(struct intel_context *ce)
                intel_timeline_put(ce->timeline);
        i915_vm_put(ce->vm);
 
+       mutex_destroy(&ce->alloc_mutex);
        mutex_destroy(&ce->pin_mutex);
        i915_active_fini(&ce->active);
 }
diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h 
b/drivers/gpu/drm/i915/gt/intel_context_types.h
index ca1420fb8b53..abae296980fa 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -72,6 +72,7 @@ struct intel_context {
 
        atomic_t pin_count;
        struct mutex pin_mutex; /* guards pinning and associated on-gpuing */
+       struct mutex alloc_mutex; /* guards against concurrent contex 
allocation */
 
        /**
         * active: Active tracker for the rq activity (inc. external) on this
-- 
2.24.1

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