drm/radeon: rework recursive gpu reset handling

Instead of all this humpy pumpy with recursive
mutex (which also fixes only halve of the problem)
move the actual gpu reset out of the fence code,
return -EDEADLK and then reset the gpu in the
calling ioctl function.

v2: Split removal of radeon_mutex into separate patch.
    Return -EAGAIN if reset is successful.

Signed-off-by: Christian König <deathsimple@vodafone.de>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_cs.c

@@ -496,6 +496,16 @@ static int radeon_cs_ib_vm_chunk(struct radeon_device *rdev,
 	return r;
 }
 
+static int radeon_cs_handle_lockup(struct radeon_device *rdev, int r)
+{
+	if (r == -EDEADLK) {
+		r = radeon_gpu_reset(rdev);
+		if (!r)
+			r = -EAGAIN;
+	}
+	return r;
+}
+
 int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 {
 	struct radeon_device *rdev = dev->dev_private;
@@ -517,6 +527,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 	if (r) {
 		DRM_ERROR("Failed to initialize parser !\n");
 		radeon_cs_parser_fini(&parser, r);
+		r = radeon_cs_handle_lockup(rdev, r);
 		radeon_mutex_unlock(&rdev->cs_mutex);
 		return r;
 	}
@@ -525,6 +536,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 		if (r != -ERESTARTSYS)
 			DRM_ERROR("Failed to parse relocation %d!\n", r);
 		radeon_cs_parser_fini(&parser, r);
+		r = radeon_cs_handle_lockup(rdev, r);
 		radeon_mutex_unlock(&rdev->cs_mutex);
 		return r;
 	}
@@ -538,6 +550,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 	}
 out:
 	radeon_cs_parser_fini(&parser, r);
+	r = radeon_cs_handle_lockup(rdev, r);
 	radeon_mutex_unlock(&rdev->cs_mutex);
 	return r;
 }

drivers/gpu/drm/radeon/radeon_device.c

@@ -986,9 +986,6 @@ int radeon_gpu_reset(struct radeon_device *rdev)
 	int r;
 	int resched;
 
-	/* Prevent CS ioctl from interfering */
-	radeon_mutex_lock(&rdev->cs_mutex);
-
 	radeon_save_bios_scratch_regs(rdev);
 	/* block TTM */
 	resched = ttm_bo_lock_delayed_workqueue(&rdev->mman.bdev);
@@ -1003,8 +1000,6 @@ int radeon_gpu_reset(struct radeon_device *rdev)
 		ttm_bo_unlock_delayed_workqueue(&rdev->mman.bdev, resched);
 	}
 
-	radeon_mutex_unlock(&rdev->cs_mutex);
-
 	if (r) {
 		/* bad news, how to tell it to userspace ? */
 		dev_info(rdev->dev, "GPU reset failed\n");

drivers/gpu/drm/radeon/radeon_fence.c

@@ -244,6 +244,8 @@ int radeon_fence_wait(struct radeon_fence *fence, bool intr)
 			/* change sequence value on all rings, so nobody else things there is a lockup */
 			for (i = 0; i < RADEON_NUM_RINGS; ++i)
 				rdev->fence_drv[i].last_seq -= 0x10000;
+
+			rdev->fence_drv[fence->ring].last_activity = jiffies;
 			write_unlock_irqrestore(&rdev->fence_lock, irq_flags);
 
 			if (radeon_ring_is_lockup(rdev, fence->ring, &rdev->ring[fence->ring])) {
@@ -254,13 +256,7 @@ int radeon_fence_wait(struct radeon_fence *fence, bool intr)
 
 				/* mark the ring as not ready any more */
 				rdev->ring[fence->ring].ready = false;
-				r = radeon_gpu_reset(rdev);
-				if (r)
-					return r;
-
-				write_lock_irqsave(&rdev->fence_lock, irq_flags);
-				rdev->fence_drv[fence->ring].last_activity = jiffies;
-				write_unlock_irqrestore(&rdev->fence_lock, irq_flags);
+				return -EDEADLK;
 			}
 		}
 	}

drivers/gpu/drm/radeon/radeon_gem.c

@@ -154,6 +154,17 @@ void radeon_gem_object_close(struct drm_gem_object *obj,
 	radeon_bo_unreserve(rbo);
 }
 
+static int radeon_gem_handle_lockup(struct radeon_device *rdev, int r)
+{
+	if (r == -EDEADLK) {
+		radeon_mutex_lock(&rdev->cs_mutex);
+		r = radeon_gpu_reset(rdev);
+		if (!r)
+			r = -EAGAIN;
+		radeon_mutex_unlock(&rdev->cs_mutex);
+	}
+	return r;
+}
 
 /*
  * GEM ioctls.
@@ -210,12 +221,14 @@ int radeon_gem_create_ioctl(struct drm_device *dev, void *data,
 					args->initial_domain, false,
 					false, &gobj);
 	if (r) {
+		r = radeon_gem_handle_lockup(rdev, r);
 		return r;
 	}
 	r = drm_gem_handle_create(filp, gobj, &handle);
 	/* drop reference from allocate - handle holds it now */
 	drm_gem_object_unreference_unlocked(gobj);
 	if (r) {
+		r = radeon_gem_handle_lockup(rdev, r);
 		return r;
 	}
 	args->handle = handle;
@@ -245,6 +258,7 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
 	r = radeon_gem_set_domain(gobj, args->read_domains, args->write_domain);
 
 	drm_gem_object_unreference_unlocked(gobj);
+	r = radeon_gem_handle_lockup(robj->rdev, r);
 	return r;
 }
 
@@ -301,6 +315,7 @@ int radeon_gem_busy_ioctl(struct drm_device *dev, void *data,
 		break;
 	}
 	drm_gem_object_unreference_unlocked(gobj);
+	r = radeon_gem_handle_lockup(robj->rdev, r);
 	return r;
 }
 
@@ -322,6 +337,7 @@ int radeon_gem_wait_idle_ioctl(struct drm_device *dev, void *data,
 	if (robj->rdev->asic->ioctl_wait_idle)
 		robj->rdev->asic->ioctl_wait_idle(robj->rdev, robj);
 	drm_gem_object_unreference_unlocked(gobj);
+	r = radeon_gem_handle_lockup(robj->rdev, r);
 	return r;
 }