9558a8e9d4
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> Link: https://lore.kernel.org/r/20230405142017.2446986-4-sth@linux.ibm.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.