drm/mode: introduce wrapper to read framebuffer refcount.

Avoids drivers knowing where the kref is stored.

[airlied: add kerneldoc]
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_crtc.c

@@ -612,7 +612,7 @@ void drm_framebuffer_remove(struct drm_framebuffer *fb)
 	 * in-use fb with fb-id == 0. Userspace is allowed to shoot its own foot
 	 * in this manner.
 	 */
-	if (atomic_read(&fb->refcount.refcount) > 1) {
+	if (drm_framebuffer_read_refcount(fb) > 1) {
 		drm_modeset_lock_all(dev);
 		/* remove from any CRTC */
 		drm_for_each_crtc(crtc, dev) {

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1917,7 +1917,7 @@ static int i915_gem_framebuffer_info(struct seq_file *m, void *data)
                          fbdev_fb->base.depth,
                          fbdev_fb->base.bits_per_pixel,
                          fbdev_fb->base.modifier[0],
-                         atomic_read(&fbdev_fb->base.refcount.refcount));
+                         drm_framebuffer_read_refcount(&fbdev_fb->base));
                describe_obj(m, fbdev_fb->obj);
                seq_putc(m, '\n');
        }
@@ -1935,7 +1935,7 @@ static int i915_gem_framebuffer_info(struct seq_file *m, void *data)
 			   fb->base.depth,
 			   fb->base.bits_per_pixel,
 			   fb->base.modifier[0],
-			   atomic_read(&fb->base.refcount.refcount));
+			   drm_framebuffer_read_refcount(&fb->base));
 		describe_obj(m, fb->obj);
 		seq_putc(m, '\n');
 	}

drivers/gpu/drm/msm/msm_fb.c

@@ -77,7 +77,7 @@ void msm_framebuffer_describe(struct drm_framebuffer *fb, struct seq_file *m)
 
 	seq_printf(m, "fb: %dx%d@%4.4s (%2d, ID:%d)\n",
 			fb->width, fb->height, (char *)&fb->pixel_format,
-			fb->refcount.refcount.counter, fb->base.id);
+			drm_framebuffer_read_refcount(fb), fb->base.id);
 
 	for (i = 0; i < n; i++) {
 		seq_printf(m, "   %d: offset=%d pitch=%d, obj: ",

drivers/gpu/drm/tegra/drm.c

@@ -878,7 +878,7 @@ static int tegra_debugfs_framebuffers(struct seq_file *s, void *data)
 		seq_printf(s, "%3d: user size: %d x %d, depth %d, %d bpp, refcount %d\n",
 			   fb->base.id, fb->width, fb->height, fb->depth,
 			   fb->bits_per_pixel,
-			   atomic_read(&fb->refcount.refcount));
+			   drm_framebuffer_read_refcount(fb));
 	}
 
 	mutex_unlock(&drm->mode_config.fb_lock);

include/drm/drm_crtc.h

@@ -2605,6 +2605,17 @@ static inline uint32_t drm_color_lut_extract(uint32_t user_input,
 	return clamp_val(val, 0, max);
 }
 
+/**
+ * drm_framebuffer_read_refcount - read the framebuffer reference count.
+ * @fb: framebuffer
+ *
+ * This functions returns the framebuffer's reference count.
+ */
+static inline uint32_t drm_framebuffer_read_refcount(struct drm_framebuffer *fb)
+{
+	return atomic_read(&fb->refcount.refcount);
+}
+
 /* Plane list iterator for legacy (overlay only) planes. */
 #define drm_for_each_legacy_plane(plane, dev) \
 	list_for_each_entry(plane, &(dev)->mode_config.plane_list, head) \