drm/i915: Refine i915_reset.lock_map

We already use a mutex to serialise i915_reset() and wedging, so all we
need it to link that into i915_request_wait() and we have our lock cycle
detection.

v2.5: Take error mutex for selftests

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614071023.17929-3-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
index 8ba7af8b7cedeb6f07660d63f099e8ecdbcc0fed..41a294f5cc1926c01822c6a5d4da257bc75dcecf 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_reset.c
+++ b/drivers/gpu/drm/i915/gt/intel_reset.c
@@ -978,7 +978,7 @@ void i915_reset(struct drm_i915_private *i915,
 
        might_sleep();
        GEM_BUG_ON(!test_bit(I915_RESET_BACKOFF, &error->flags));
-       lock_map_acquire(&i915->gt.reset_lockmap);
+       mutex_lock(&error->wedge_mutex);
 
        /* Clear any previous failed attempts at recovery. Time to try again. */
        if (!__i915_gem_unset_wedged(i915))
@@ -1031,7 +1031,7 @@ void i915_reset(struct drm_i915_private *i915,
 finish:
        reset_finish(i915);
 unlock:
-       lock_map_release(&i915->gt.reset_lockmap);
+       mutex_unlock(&error->wedge_mutex);
        return;
 
 taint:
@@ -1147,9 +1147,7 @@ static void i915_reset_device(struct drm_i915_private *i915,
                /* Flush everyone using a resource about to be clobbered */
                synchronize_srcu_expedited(&error->reset_backoff_srcu);
 
-               mutex_lock(&error->wedge_mutex);
                i915_reset(i915, engine_mask, reason);
-               mutex_unlock(&error->wedge_mutex);
 
                intel_finish_reset(i915);
        }

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 90d94d904e65723db11ffdb7a98b695d213e9bf7..3683ef6d4c28d4c6629399ede59c2c83478d8647 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1901,14 +1901,6 @@ struct drm_i915_private {
                ktime_t last_init_time;
 
                struct i915_vma *scratch;
-
-               /*
-                * We must never wait on the GPU while holding a lock as we
-                * may need to perform a GPU reset. So while we don't need to
-                * serialise wait/reset with an explicit lock, we do want
-                * lockdep to detect potential dependency cycles.
-                */
-               struct lockdep_map reset_lockmap;
        } gt;
 
        struct {

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 4bbded4aa9363051e427ac303a3dad2a9d31a9c0..7232361973fd4efeaa470c11846ee88ef5c13c3a 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1746,7 +1746,6 @@ static void i915_gem_init__mm(struct drm_i915_private *i915)
 
 int i915_gem_init_early(struct drm_i915_private *dev_priv)
 {
-       static struct lock_class_key reset_key;
        int err;
 
        intel_gt_pm_init(dev_priv);
@@ -1754,8 +1753,6 @@ int i915_gem_init_early(struct drm_i915_private *dev_priv)
        INIT_LIST_HEAD(&dev_priv->gt.active_rings);
        INIT_LIST_HEAD(&dev_priv->gt.closed_vma);
        spin_lock_init(&dev_priv->gt.closed_lock);
-       lockdep_init_map(&dev_priv->gt.reset_lockmap,
-                        "i915.reset", &reset_key, 0);
 
        i915_gem_init__mm(dev_priv);
        i915_gem_init__pm(dev_priv);

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 5ee1ef92a9d92d4938f90de815ad78e3a6de665d..da76e4d1c7f172097e9544782659b4ceccd22b3b 100644 (file)
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1444,7 +1444,15 @@ long i915_request_wait(struct i915_request *rq,
                return -ETIME;
 
        trace_i915_request_wait_begin(rq, flags);
-       lock_map_acquire(&rq->i915->gt.reset_lockmap);
+
+       /*
+        * We must never wait on the GPU while holding a lock as we
+        * may need to perform a GPU reset. So while we don't need to
+        * serialise wait/reset with an explicit lock, we do want
+        * lockdep to detect potential dependency cycles.
+        */
+       mutex_acquire(&rq->i915->gpu_error.wedge_mutex.dep_map,
+                     0, 0, _THIS_IP_);
 
        /*
         * Optimistic spin before touching IRQs.
@@ -1520,7 +1528,7 @@ long i915_request_wait(struct i915_request *rq,
        dma_fence_remove_callback(&rq->fence, &wait.cb);
 
 out:
-       lock_map_release(&rq->i915->gt.reset_lockmap);
+       mutex_release(&rq->i915->gpu_error.wedge_mutex.dep_map, 0, _THIS_IP_);
        trace_i915_request_wait_end(rq);
        return timeout;
 }

diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
index 1e9ffced78c129064aaf96e00ec1a8009cb209f5..b7f3fbb4ae89f43f7f63c5f9cb82fd1c50e0c8db 100644 (file)
--- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
+++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
@@ -130,7 +130,6 @@ static struct dev_pm_domain pm_domain = {
 
 struct drm_i915_private *mock_gem_device(void)
 {
-       static struct lock_class_key reset_key;
        struct drm_i915_private *i915;
        struct pci_dev *pdev;
        int err;
@@ -205,7 +204,6 @@ struct drm_i915_private *mock_gem_device(void)
        INIT_LIST_HEAD(&i915->gt.active_rings);
        INIT_LIST_HEAD(&i915->gt.closed_vma);
        spin_lock_init(&i915->gt.closed_lock);
-       lockdep_init_map(&i915->gt.reset_lockmap, "i915.reset", &reset_key, 0);
 
        mutex_lock(&i915->drm.struct_mutex);