Michael Ellerman <m...@ellerman.id.au> writes:
> Nathan Lynch <nath...@linux.ibm.com> writes:
>> The behavior of rtas_ibm_suspend_me_unsafe() is to return -EAGAIN to
>> the caller until the specified VASI suspend session state makes the
>> transition from H_VASI_ENABLED to H_VASI_SUSPENDING. In the interest
>> of separating concerns to prepare for a new implementation of the
>> join/suspend sequence, extract VASI session polling logic into a
>> couple of local functions. Waiting for the session state to reach
>> H_VASI_SUSPENDING before calling rtas_ibm_suspend_me_unsafe() ensures
>> that we will never get an EAGAIN result necessitating a retry. No
>> user-visible change in behavior is intended.
>>
>> Signed-off-by: Nathan Lynch <nath...@linux.ibm.com>
>> ---
>> arch/powerpc/platforms/pseries/mobility.c | 76 +++++++++++++++++++++--
>> 1 file changed, 71 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/mobility.c
>> b/arch/powerpc/platforms/pseries/mobility.c
>> index dc6abf164db7..1b8ae221b98a 100644
>> --- a/arch/powerpc/platforms/pseries/mobility.c
>> +++ b/arch/powerpc/platforms/pseries/mobility.c
>> @@ -345,6 +345,73 @@ void post_mobility_fixup(void)
> ...
>
>> +
>> +static int wait_for_vasi_session_suspending(u64 handle)
>> +{
>> + unsigned long state;
>> + bool keep_polling;
>> + int ret;
>> +
>> + /*
>> + * Wait for transition from H_VASI_ENABLED to
>> + * H_VASI_SUSPENDING. Treat anything else as an error.
>> + */
>> + do {
>> + keep_polling = false;
>> + ret = poll_vasi_state(handle, &state);
>> + if (ret != 0)
>> + break;
>> +
>> + switch (state) {
>> + case H_VASI_SUSPENDING:
>> + break;
>> + case H_VASI_ENABLED:
>> + keep_polling = true;
>> + ssleep(1);
>> + break;
>> + default:
>> + pr_err("unexpected H_VASI_STATE result %lu\n", state);
>> + ret = -EIO;
>> + break;
>> + }
>> + } while (keep_polling);
>
> This seems like it could be simpler?
>
> eg:
>
> while (true) {
> ret = poll_vasi_state(handle, &state);
>
> if (ret != 0 || state == H_VASI_SUSPENDING)
> break;
> else if (state == H_VASI_ENABLED)
> ssleep(1);
> else {
> pr_err("unexpected H_VASI_STATE result %lu\n", state);
> ret = -EIO;
> break;
> }
> }
>
>
> Or did I miss something?
No I think you're right, thanks.
