Commit 13fe8e68 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

ublk: add UBLK_CMD_DEL_DEV_ASYNC 



The current command UBLK_CMD_DEL_DEV won't return until the device is
released, this way looks more reliable, but makes userspace more
difficult to implement, especially about orders: unmap command
buffer(which holds one ublkc reference), ublkc close,
io_uring_file_unregister, ublkb close.

Add UBLK_CMD_DEL_DEV_ASYNC so that device deletion won't wait release,
then userspace needn't worry about the above order. Actually both loop
and nbd is deleted in this async way.

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20240223075539.89945-3-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 1221b9e9

drivers/block/ublk_drv.c

+6 −3
Original line number Diff line number Diff line
@@ -2468,7 +2468,7 @@ static inline bool ublk_idr_freed(int id) 
	return ptr == NULL;

}



static int ublk_ctrl_del_dev(struct ublk_device **p_ub)

static int ublk_ctrl_del_dev(struct ublk_device **p_ub, bool wait)

{

	struct ublk_device *ub = *p_ub;

	int idx = ub->ub_number;
@@ -2502,7 +2502,7 @@ static int ublk_ctrl_del_dev(struct ublk_device **p_ub) 
	 * - the device number is freed already, we will not find this

	 *   device via ublk_get_device_from_id()

	 */

	if (wait_event_interruptible(ublk_idr_wq, ublk_idr_freed(idx)))

	if (wait && wait_event_interruptible(ublk_idr_wq, ublk_idr_freed(idx)))

		return -EINTR;

	return 0;

}
@@ -2901,7 +2901,10 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, 
		ret = ublk_ctrl_add_dev(cmd);

		break;

	case UBLK_CMD_DEL_DEV:

		ret = ublk_ctrl_del_dev(&ub);

		ret = ublk_ctrl_del_dev(&ub, true);

		break;

	case UBLK_U_CMD_DEL_DEV_ASYNC:

		ret = ublk_ctrl_del_dev(&ub, false);

		break;

	case UBLK_CMD_GET_QUEUE_AFFINITY:

		ret = ublk_ctrl_get_queue_affinity(ub, cmd);

include/uapi/linux/ublk_cmd.h

+2 −0
Original line number Diff line number Diff line
@@ -49,6 +49,8 @@ 
	_IOR('u', UBLK_CMD_GET_DEV_INFO2, struct ublksrv_ctrl_cmd)

#define UBLK_U_CMD_GET_FEATURES	\

	_IOR('u', 0x13, struct ublksrv_ctrl_cmd)

#define UBLK_U_CMD_DEL_DEV_ASYNC	\

	_IOR('u', 0x14, struct ublksrv_ctrl_cmd)



/*

 * 64bits are enough now, and it should be easy to extend in case of