drm/i915: Mark a few functions as __must_check

... to benefit from the compiler checking that we remember to handle
and propagate errors.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_drv.h

@@ -1093,11 +1093,11 @@ int i915_gem_init_object(struct drm_gem_object *obj);
 struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 						  size_t size);
 void i915_gem_free_object(struct drm_gem_object *obj);
-int i915_gem_object_pin(struct drm_i915_gem_object *obj,
-			uint32_t alignment,
-			bool map_and_fenceable);
+int __must_check i915_gem_object_pin(struct drm_i915_gem_object *obj,
+				     uint32_t alignment,
+				     bool map_and_fenceable);
 void i915_gem_object_unpin(struct drm_i915_gem_object *obj);
-int i915_gem_object_unbind(struct drm_i915_gem_object *obj);
+int __must_check i915_gem_object_unbind(struct drm_i915_gem_object *obj);
 void i915_gem_release_mmap(struct drm_i915_gem_object *obj);
 void i915_gem_lastclose(struct drm_device *dev);
 
@@ -1110,37 +1110,42 @@ i915_seqno_passed(uint32_t seq1, uint32_t seq2)
 	return (int32_t)(seq1 - seq2) >= 0;
 }
 
-int i915_gem_object_get_fence_reg(struct drm_i915_gem_object *obj,
-				  bool interruptible);
-int i915_gem_object_put_fence_reg(struct drm_i915_gem_object *obj,
-				  bool interruptible);
+int __must_check i915_gem_object_get_fence_reg(struct drm_i915_gem_object *obj,
+					       bool interruptible);
+int __must_check i915_gem_object_put_fence_reg(struct drm_i915_gem_object *obj,
+					       bool interruptible);
+
 void i915_gem_retire_requests(struct drm_device *dev);
 void i915_gem_reset(struct drm_device *dev);
 void i915_gem_clflush_object(struct drm_i915_gem_object *obj);
-int i915_gem_object_set_domain(struct drm_i915_gem_object *obj,
-			       uint32_t read_domains,
-			       uint32_t write_domain);
-int i915_gem_object_flush_gpu(struct drm_i915_gem_object *obj,
-			      bool interruptible);
-int i915_gem_init_ringbuffer(struct drm_device *dev);
+int __must_check i915_gem_object_set_domain(struct drm_i915_gem_object *obj,
+					    uint32_t read_domains,
+					    uint32_t write_domain);
+int __must_check i915_gem_object_flush_gpu(struct drm_i915_gem_object *obj,
+					   bool interruptible);
+int __must_check i915_gem_init_ringbuffer(struct drm_device *dev);
 void i915_gem_cleanup_ringbuffer(struct drm_device *dev);
-int i915_gem_do_init(struct drm_device *dev, unsigned long start,
-		     unsigned long mappable_end, unsigned long end);
-int i915_gpu_idle(struct drm_device *dev);
-int i915_gem_idle(struct drm_device *dev);
-int i915_add_request(struct drm_device *dev,
-		     struct drm_file *file_priv,
-		     struct drm_i915_gem_request *request,
-		     struct intel_ring_buffer *ring);
-int i915_do_wait_request(struct drm_device *dev,
-			 uint32_t seqno,
-			 bool interruptible,
-			 struct intel_ring_buffer *ring);
+void i915_gem_do_init(struct drm_device *dev,
+		      unsigned long start,
+		      unsigned long mappable_end,
+		      unsigned long end);
+int __must_check i915_gpu_idle(struct drm_device *dev);
+int __must_check i915_gem_idle(struct drm_device *dev);
+int __must_check i915_add_request(struct drm_device *dev,
+				  struct drm_file *file_priv,
+				  struct drm_i915_gem_request *request,
+				  struct intel_ring_buffer *ring);
+int __must_check i915_do_wait_request(struct drm_device *dev,
+				      uint32_t seqno,
+				      bool interruptible,
+				      struct intel_ring_buffer *ring);
 int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf);
-int i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj,
-				      int write);
-int i915_gem_object_set_to_display_plane(struct drm_i915_gem_object *obj,
-					 struct intel_ring_buffer *pipelined);
+int __must_check
+i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj,
+				  bool write);
+int __must_check
+i915_gem_object_set_to_display_plane(struct drm_i915_gem_object *obj,
+				     struct intel_ring_buffer *pipelined);
 int i915_gem_attach_phys_object(struct drm_device *dev,
 				struct drm_i915_gem_object *obj,
 				int id,
@@ -1152,14 +1157,16 @@ void i915_gem_release(struct drm_device *dev, struct drm_file *file);
 
 /* i915_gem_gtt.c */
 void i915_gem_restore_gtt_mappings(struct drm_device *dev);
-int i915_gem_gtt_bind_object(struct drm_i915_gem_object *obj);
+int __must_check i915_gem_gtt_bind_object(struct drm_i915_gem_object *obj);
 void i915_gem_gtt_unbind_object(struct drm_i915_gem_object *obj);
 
 /* i915_gem_evict.c */
-int i915_gem_evict_something(struct drm_device *dev, int min_size,
-			     unsigned alignment, bool mappable);
-int i915_gem_evict_everything(struct drm_device *dev, bool purgeable_only);
-int i915_gem_evict_inactive(struct drm_device *dev, bool purgeable_only);
+int __must_check i915_gem_evict_something(struct drm_device *dev, int min_size,
+					  unsigned alignment, bool mappable);
+int __must_check i915_gem_evict_everything(struct drm_device *dev,
+					   bool purgeable_only);
+int __must_check i915_gem_evict_inactive(struct drm_device *dev,
+					 bool purgeable_only);
 
 /* i915_gem_tiling.c */
 void i915_gem_detect_bit_6_swizzle(struct drm_device *dev);

drivers/gpu/drm/i915/i915_gem.c

@@ -215,27 +215,19 @@ i915_gem_object_is_inactive(struct drm_i915_gem_object *obj)
 	return obj->gtt_space && !obj->active && obj->pin_count == 0;
 }
 
-int i915_gem_do_init(struct drm_device *dev,
-		     unsigned long start,
-		     unsigned long mappable_end,
-		     unsigned long end)
+void i915_gem_do_init(struct drm_device *dev,
+		      unsigned long start,
+		      unsigned long mappable_end,
+		      unsigned long end)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 
-	if (start >= end ||
-	    (start & (PAGE_SIZE - 1)) != 0 ||
-	    (end & (PAGE_SIZE - 1)) != 0) {
-		return -EINVAL;
-	}
-
 	drm_mm_init(&dev_priv->mm.gtt_space, start,
 		    end - start);
 
 	dev_priv->mm.gtt_total = end - start;
 	dev_priv->mm.mappable_gtt_total = min(end, mappable_end) - start;
 	dev_priv->mm.gtt_mappable_end = mappable_end;
-
-	return 0;
 }
 
 int
@@ -243,13 +235,16 @@ i915_gem_init_ioctl(struct drm_device *dev, void *data,
 		    struct drm_file *file)
 {
 	struct drm_i915_gem_init *args = data;
-	int ret;
+
+	if (args->gtt_start >= args->gtt_end ||
+	    (args->gtt_end | args->gtt_start) & (PAGE_SIZE - 1))
+		return -EINVAL;
 
 	mutex_lock(&dev->struct_mutex);
-	ret = i915_gem_do_init(dev, args->gtt_start, args->gtt_end, args->gtt_end);
+	i915_gem_do_init(dev, args->gtt_start, args->gtt_end, args->gtt_end);
 	mutex_unlock(&dev->struct_mutex);
 
-	return ret;
+	return 0;
 }
 
 int
@@ -2949,7 +2944,7 @@ i915_gem_object_flush_cpu_write_domain(struct drm_i915_gem_object *obj)
  * flushes to occur.
  */
 int
-i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, int write)
+i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, bool write)
 {
 	uint32_t old_write_domain, old_read_domains;
 	int ret;
@@ -5177,8 +5172,8 @@ i915_gem_inactive_shrink(struct shrinker *shrinker,
 				 &dev_priv->mm.inactive_list,
 				 mm_list) {
 		if (i915_gem_object_is_purgeable(obj)) {
-			i915_gem_object_unbind(obj);
-			if (--nr_to_scan == 0)
+			if (i915_gem_object_unbind(obj) == 0 &&
+			    --nr_to_scan == 0)
 				break;
 		}
 	}
@@ -5188,10 +5183,10 @@ i915_gem_inactive_shrink(struct shrinker *shrinker,
 	list_for_each_entry_safe(obj, next,
 				 &dev_priv->mm.inactive_list,
 				 mm_list) {
-		if (nr_to_scan) {
-			i915_gem_object_unbind(obj);
+		if (nr_to_scan &&
+		    i915_gem_object_unbind(obj) == 0)
 			nr_to_scan--;
-		} else
+		else
 			cnt++;
 	}