[PATCH v2] powerpc/fadump: return error when fadump registration fails

[Mahesh Jagannath Salgaonkar]

On 05/27/2017 09:16 PM, Michal Suchanek wrote:
>  - log an error message when registration fails and no error code listed
>  in the switch is returned
>  - translate the hv error code to posix error code and return it from
>  fw_register
>  - return the posix error code from fw_register to the process writing
>  to sysfs
>  - return EEXIST on re-registration
>  - return success on deregistration when fadump is not registered
>  - return ENODEV when no memory is reserved for fadump

Why do we need this ? Userspace can always read back the fadump
registration status from /sys/kernel/fadump_registered (after echo 1 to
it) to find out whether fadump registration succeeded or not.

 /sys/kernel/fadump_registered

    This is used to display the fadump registration status as well
    as to control (start/stop) the fadump registration.
    0 = fadump is not registered.
    1 = fadump is registered and ready to handle system crash.

-Mahesh.