blk_check_plugged
EXPORT_SYMBOL(blk_check_plugged);
struct blk_plug_cb *cb = blk_check_plugged(drbd_unplug, resource, sizeof(*plug));
cb = blk_check_plugged(unplug, mddev, sizeof(*plug));
struct blk_plug_cb *blk_cb = blk_check_plugged(
cb = blk_check_plugged(raid_unplug, fs_info, sizeof(*plug));
extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,