Extern or forward variable declaration at include/linux/device-mapper.h, line 18 References: drivers/md/dm-crypt.c, line 355 drivers/md/dm-crypt.c, line 356 drivers/md/dm-crypt.c, line 531 drivers/md/dm-crypt.c, line 668 drivers/md/dm-crypt.c, line 1302 drivers/md/dm-io.c, line 200 drivers/md/dm-io.c, line 200 drivers/md/dm-io.c, line 208 drivers/md/dm-io.c, line 208 drivers/md/dm-io.c, line 212 drivers/md/dm-linear.c, line 123 drivers/md/dm.c, line 1016 drivers/md/dm.c, line 1175 drivers/md/dm.c, line 1255 include/linux/device-mapper.h, line 18 include/linux/device-mapper.h, line 83