drm/i915: Mark up all locked waiters

In the next patch we want to handle reset directly by a locked waiter in
order to avoid issues with returning before the reset is handled. To
handle the reset, we must first know whether we hold the struct_mutex.
If we do not hold the struct_mtuex we can not perform the reset, but we do
not block the reset worker either (and so we can just continue to wait for
request completion) - otherwise we must relinquish the mutex.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160909131201.16673-10-chris@chris-wilson.co.uk

8 files changed, 38 insertions, 14 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 0e4cbad7a883..6a270bc0fdb3 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4794,7 +4794,9 @@ i915_drop_caches_set(void *data, u64 val)
                 return ret;
 
         if (val & DROP_ACTIVE) {
-                ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_INTERRUPTIBLE);
+                ret = i915_gem_wait_for_idle(dev_priv,
+                                             I915_WAIT_INTERRUPTIBLE |
+                                             I915_WAIT_LOCKED);
                 if (ret)
                         goto unlock;
         }
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 4617250c3000..23069a2d2850 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2802,7 +2802,8 @@ __i915_gem_object_sync(struct drm_i915_gem_request *to,
 
         if (!i915.semaphores) {
                 ret = i915_wait_request(from,
-                                        from->i915->mm.interruptible,
+                                        from->i915->mm.interruptible |
+                                        I915_WAIT_LOCKED,
                                         NULL,
                                         NO_WAITBOOST);
                 if (ret)
@@ -4304,7 +4305,9 @@ int i915_gem_suspend(struct drm_device *dev)
         if (ret)
                 goto err;
 
-        ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_INTERRUPTIBLE);
+        ret = i915_gem_wait_for_idle(dev_priv,
+                                     I915_WAIT_INTERRUPTIBLE |
+                                     I915_WAIT_LOCKED);
         if (ret)
                 goto err;
 
diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index 103085246975..5b6f81c1dbca 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -170,7 +170,9 @@ search_again:
         if (ret)
                 return ret;
 
-        ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_INTERRUPTIBLE);
+        ret = i915_gem_wait_for_idle(dev_priv,
+                                     I915_WAIT_INTERRUPTIBLE |
+                                     I915_WAIT_LOCKED);
         if (ret)
                 return ret;
 
@@ -275,7 +277,9 @@ int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
                                 return ret;
                 }
 
-                ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_INTERRUPTIBLE);
+                ret = i915_gem_wait_for_idle(dev_priv,
+                                             I915_WAIT_INTERRUPTIBLE |
+                                             I915_WAIT_LOCKED);
                 if (ret)
                         return ret;
 
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 9bcac52b8268..f3c6876da521 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2683,7 +2683,7 @@ void i915_gem_gtt_finish_object(struct drm_i915_gem_object *obj)
         struct i915_ggtt *ggtt = &dev_priv->ggtt;
 
         if (unlikely(ggtt->do_idle_maps)) {
-                if (i915_gem_wait_for_idle(dev_priv, 0)) {
+                if (i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED)) {
                         DRM_ERROR("Failed to wait for idle; VT'd may hang.\n");
                         /* Wait a bit, in hopes it avoids the hang */
                         udelay(10);
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index f4c15f319d08..5f89801e6a16 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -260,7 +260,9 @@ static int i915_gem_init_seqno(struct drm_i915_private *dev_priv, u32 seqno)
 
         /* Carefully retire all requests without writing to the rings */
         for_each_engine(engine, dev_priv) {
-                ret = intel_engine_idle(engine, I915_WAIT_INTERRUPTIBLE);
+                ret = intel_engine_idle(engine,
+                                        I915_WAIT_INTERRUPTIBLE |
+                                        I915_WAIT_LOCKED);
                 if (ret)
                         return ret;
         }
@@ -625,6 +627,10 @@ int i915_wait_request(struct drm_i915_gem_request *req,
         int ret = 0;
 
         might_sleep();
+#if IS_ENABLED(CONFIG_LOCKDEP)
+        GEM_BUG_ON(!!lockdep_is_held(&req->i915->drm.struct_mutex) !=
+                   !!(flags & I915_WAIT_LOCKED));
+#endif
 
         if (i915_gem_request_completed(req))
                 return 0;
@@ -667,7 +673,8 @@ int i915_wait_request(struct drm_i915_gem_request *req,
                 goto complete;
 
         set_current_state(state);
-        add_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
+        if (flags & I915_WAIT_LOCKED)
+                add_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
 
         intel_wait_init(&wait, req->fence.seqno);
         if (intel_engine_add_wait(req->engine, &wait))
@@ -707,10 +714,12 @@ wakeup:
                 if (i915_spin_request(req, state, 2))
                         break;
         }
-        remove_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
 
         intel_engine_remove_wait(req->engine, &wait);
+        if (flags & I915_WAIT_LOCKED)
+                remove_wait_queue(&req->i915->gpu_error.wait_queue, &reset);
         __set_current_state(TASK_RUNNING);
+
 complete:
         trace_i915_gem_request_wait_end(req);
 
diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h
index 479896ef791e..def35721e9ed 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.h
+++ b/drivers/gpu/drm/i915/i915_gem_request.h
@@ -222,7 +222,8 @@ int i915_wait_request(struct drm_i915_gem_request *req,
                       s64 *timeout,
                       struct intel_rps_client *rps)
         __attribute__((nonnull(1)));
-#define I915_WAIT_INTERRUPTIBLE BIT(0)
+#define I915_WAIT_INTERRUPTIBLE BIT(0)
+#define I915_WAIT_LOCKED        BIT(1) /* struct_mutex held, handle GPU reset */
 
 static inline u32 intel_engine_get_seqno(struct intel_engine_cs *engine);
 
@@ -576,7 +577,9 @@ i915_gem_active_wait(const struct i915_gem_active *active, struct mutex *mutex)
         if (!request)
                 return 0;
 
-        return i915_wait_request(request, I915_WAIT_INTERRUPTIBLE, NULL, NULL);
+        return i915_wait_request(request,
+                                 I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
+                                 NULL, NULL);
 }
 
 /**
@@ -639,7 +642,9 @@ i915_gem_active_retire(struct i915_gem_active *active,
         if (!request)
                 return 0;
 
-        ret = i915_wait_request(request, I915_WAIT_INTERRUPTIBLE, NULL, NULL);
+        ret = i915_wait_request(request,
+                                I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
+                                NULL, NULL);
         if (ret)
                 return ret;
 
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 35a05f4c51c1..1c237d02f30b 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -414,7 +414,7 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr
                 return NOTIFY_DONE;
 
         /* Force everything onto the inactive lists */
-        ret = i915_gem_wait_for_idle(dev_priv, 0);
+        ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED);
         if (ret)
                 goto out;
 
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index a5bf18877068..8687a84a7ff3 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -2223,7 +2223,8 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
         if (WARN_ON(&target->ring_link == &ring->request_list))
                 return -ENOSPC;
 
-        ret = i915_wait_request(target, I915_WAIT_INTERRUPTIBLE,
+        ret = i915_wait_request(target,
+                                I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
                                 NULL, NO_WAITBOOST);
         if (ret)
                 return ret;