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ublk: add UBLK_CMD_DEL_DEV_ASYNC

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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: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20240223075539.89945-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2024-02-23 15:55:39 +08:00 committed by Jens Axboe
parent 1221b9e982
commit 13fe8e6825
2 changed files with 8 additions and 3 deletions
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9
drivers/block/ublk_drv.c
View File

@ -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);

2
include/uapi/linux/ublk_cmd.h
View File

@ -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