drm/framebuffer: Print task that allocated the fb in debug info.

This is is very useful to finding sources of leaked framebufers.
The fbcon fb is annotated with [fbcon], to give it a better name
than kworker.

Signed-off-by: Maarten Lankhorst <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Reviewed-by: Daniel Vetter <[e-mail]>

drivers/gpu/drm/drm_fb_helper.c

···
 	if (ret < 0)
 		return ret;
 
+	strcpy(fb_helper->fb->comm, "[fbcon]");
 	return 0;
 }
 

drivers/gpu/drm/drm_framebuffer.c

···
 	INIT_LIST_HEAD(&fb->filp_head);
 
 	fb->funcs = funcs;
+	strcpy(fb->comm, current->comm);
 
 	ret = __drm_mode_object_add(dev, &fb->base, DRM_MODE_OBJECT_FB,
 				    false, drm_framebuffer_free);
···
 	struct drm_format_name_buf format_name;
 	unsigned int i;
 
+	drm_printf_indent(p, indent, "allocated by = %s\n", fb->comm);
 	drm_printf_indent(p, indent, "refcount=%u\n",
 			  drm_framebuffer_read_refcount(fb));
 	drm_printf_indent(p, indent, "format=%s\n",

include/drm/drm_framebuffer.h

···
 	 * @base: base modeset object structure, contains the reference count.
 	 */
 	struct drm_mode_object base;
+
+	/**
+	 * @comm: Name of the process allocating the fb, used for fb dumping.
+	 */
+	char comm[TASK_COMM_LEN];
+
 	/**
 	 * @format: framebuffer format information
 	 */