On Fri, 15 Nov 2019 03:56:13 +0100 Eric Farman <farman@xxxxxxxxxxxxx> wrote: > From: Farhan Ali <alifm@xxxxxxxxxxxxx> > > The subchannel logical path mask (lpm) would have the most > up to date information of channel paths that are logically > available for the subchannel. > > Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxx> > Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx> > --- > > Notes: > v0->v1: [EF] > - None; however I am greatly confused by this one. Thoughts? I think it's actually wrong. > > drivers/s390/cio/vfio_ccw_cp.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c > index 3645d1720c4b..d4a86fb9d162 100644 > --- a/drivers/s390/cio/vfio_ccw_cp.c > +++ b/drivers/s390/cio/vfio_ccw_cp.c > @@ -779,9 +779,7 @@ union orb *cp_get_orb(struct channel_program *cp, u32 intparm, u8 lpm) > orb->cmd.intparm = intparm; > orb->cmd.fmt = 1; > orb->cmd.key = PAGE_DEFAULT_KEY >> 4; > - > - if (orb->cmd.lpm == 0) > - orb->cmd.lpm = lpm; In the end, the old code will use the lpm from the subchannel structure, if userspace did not supply anything to be used. > + orb->cmd.lpm = lpm; The new code will always discard any lpm userspace has supplied and replace it with the lpm from the subchannel structure. This feels wrong; what if the I/O is supposed to be restricted to a subset of the paths? If we want to include the current value of the subchannel lpm in the requests, we probably want to AND the masks instead. > > chain = list_first_entry(&cp->ccwchain_list, struct ccwchain, next); > cpa = chain->ch_ccw;
