Re: [PATCH 3/7] s390/dasd: add aq_mask sysfs attribute

[Halil Pasic <pasic@linux.ibm.com>]

On Wed,  5 Apr 2023 16:20:13 +0200
Stefan Haberland <sth@linux.ibm.com> wrote:

> Add sysfs attribute that controls the DASD autoquiesce feature.
> The autoquiesce is disabled when 0 is echoed to the attribute.
> 
> A value greater than 0 will enable the feature.
> The aq_mask attribute will accept an unsigned integer and the value
> will be interpreted as bitmask defining the trigger events that will
> lead to an automatic quiesce.
> 
> The following autoquiesce triggers will currently be available:
> 
> DASD_EER_FATALERROR  1 - any final I/O error
> DASD_EER_NOPATH      2 - no remaining paths for the device
> DASD_EER_STATECHANGE 3 - a state change interrupt occurred
> DASD_EER_PPRCSUSPEND 4 - the device is PPRC suspended
> DASD_EER_NOSPC       5 - there is no space remaining on an ESE device
> DASD_EER_TIMEOUT     6 - a certain amount of timeouts occurred
> DASD_EER_STARTIO     7 - the IO start function encountered an error
> 
> The currently supported maximum value is 255.
> 
> Bit 31 is reserved for internal usage.
> Bit 0 is not used.
> 
> Example:
> 
>  - deactivate autoquiesce
>    $ echo 0 > /sys/bus/ccw/0.0.1234/aq_mask
> 
>  - enable autoquiesce for FATALERROR, NOPATH and TIMEOUT
>    (0000 0000 0000 0000  0000 0000 0100 0110 => 70)
>    $ echo 70 > /sys/bus/ccw/0.0.1234/aq_mask
> 
> Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
> Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>

Reviewed-by: Halil Pasic <pasic@linux.ibm.com>

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