Re: [PATCH 7.1 667/744] ptp: ptp_s390: Add missing facility check

Greg Kroah-Hartman <[email protected]> writes:

> On Fri, Jul 31, 2026 at 08:21:26AM +0200, Jiri Slaby wrote:
>> On 30. 07. 26, 16:15, Greg Kroah-Hartman wrote:
>> > 7.1-stable review patch.  If anyone has any objections, please let me know.
>> > 
>> > ------------------
>> > 
>> > From: Sven Schnelle <[email protected]>
>> > 
>> > commit e78f1ac37afcb16cb6fef8a2c92591eab6558956 upstream.
>> > 
>> > Only register the physical clock when facility 28 is installed
>> > and PTFF QAF returns that PTFF QPT is available.
>> > 
>> > Fixes: 2d7de7a3010d ("s390/time: Add PtP driver")
>> > Signed-off-by: Sven Schnelle <[email protected]>
>> > Cc: [email protected]
>> > Reviewed-by: Heiko Carstens <[email protected]>
>> > Link: https://patch.msgid.link/[email protected]
>> > Signed-off-by: Jakub Kicinski <[email protected]>
>> > Signed-off-by: Greg Kroah-Hartman <[email protected]>
>> > ---
>> >   drivers/ptp/ptp_s390.c |    6 +++++-
>> >   1 file changed, 5 insertions(+), 1 deletion(-)
>> > 
>> > --- a/drivers/ptp/ptp_s390.c
>> > +++ b/drivers/ptp/ptp_s390.c
>> > @@ -107,6 +107,9 @@ static __init int ptp_s390_init(void)
>> >   	if (IS_ERR(ptp_stcke_clock))
>> >   		return PTR_ERR(ptp_stcke_clock);
>> > +	if (!test_facility(28) || !ptff_query(PTFF_QPT))
>> 
>> ptff_query() here needs:
>> 9de445d8296a ("s390/ptff: Export ptff_function_mask[]")
>
> Ah, good catch, now queued up.  How did you find that thing?

Maybe we should change the documentation. I was wondering whether I have
to mark that as a dependency, looked up ./process/stable-kernel-rules.rst
which says:

  Note that for a patch series, you do not have to list as prerequisites the
  patches present in the series itself. For example, if you have the following
  patch series::

    patch1
    patch2

  where patch2 depends on patch1, you do not have to list patch1 as
  prerequisite of patch2 if you have already marked patch1 for stable
  inclusion.

Which lead me to believe that I don't have to add stable@ to the the
other patch, but looks like this was wrong?