Re: [PATCH] scsi: core: Allow the state change from SDEV_QUIESCE to SDEV_BLOCK

[Ming Lei <ming.lei@redhat.com>]

On Fri, Apr 17, 2020 at 05:40:45PM -0700, Dexuan Cui wrote:
> The APIs scsi_host_block()/scsi_host_unblock() are recently added by:
> 2bb955840c1d ("scsi: core: add scsi_host_(block,unblock) helper function")
> and so far the APIs are only used by:
> 3d3ca53b1639 ("scsi: aacraid: use scsi_host_(block,unblock) to block I/O")
> 
> However, from reading the code, I think the APIs don't really work for
> aacraid, because, in the resume path of hibernation, when aac_suspend() ->
> scsi_host_block() is called, scsi_device_quiesce() has set the state to
> SDEV_QUIESCE, so aac_suspend() -> scsi_host_block() returns -EINVAL.
> 
> Fix the issue by allowing the state change.
> 
> Fixes: 2bb955840c1d ("scsi: core: add scsi_host_(block,unblock) helper function")
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> ---
>  drivers/scsi/scsi_lib.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 47835c4b4ee0..06c260f6cdae 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -2284,6 +2284,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
>  		switch (oldstate) {
>  		case SDEV_RUNNING:
>  		case SDEV_CREATED_BLOCK:
> +		case SDEV_QUIESCE:
>  		case SDEV_OFFLINE:
>  			break;
>  		default:

Looks reasonable because SDEV_BLOCK is one more strict state than
QEIESCE, so:

Reviewed-by: Ming Lei <ming.lei@redha.com>


Thanks,
Ming