Re: [PATCH 1/2] scsi: core: scsi_device_online() return false if state is SDEV_CANCEL

[Bart Van Assche <bvanassche@xxxxxxx>]

On 9/22/23 02:36, Wenchao Hao wrote:
> SDEV_CANCEL is set when removing device and scsi_device_online() should
> return false if sdev_state is SDEV_CANCEL.
>
> IO hang would be caused if return true when state is SDEV_CANCEL with
> following order:
>
> T1:					    T2:scsi_error_handler
> __scsi_remove_device()
>    scsi_device_set_state(sdev, SDEV_CANCEL)
>    					    scsi_eh_flush_done_q()
> 					    if (scsi_device_online(sdev))
> 					      scsi_queue_insert(scmd,...)
>
> The command added by scsi_queue_insert() would never be handled any
> more.

Why not? I think the blk_mq_destroy_queue() call in 
__scsi_remove_device() will cause it to fail.

Thanks,

Bart.