On Mon, Nov 22 2021, Vineeth Vijayan <vneethv@xxxxxxxxxxxxx> wrote:
> commit fa1a8c23eb7d ("s390: cio: Delay uevents for subchannels")
> introduced suppression of uevents for a subchannel until after it is
> clear that the subchannel would not be unregistered again
> immediately. This was done to avoid uevents being generated for I/O
> subchannels with no valid device, which can happen on LPAR.
>
> However, this also has some drawbacks: All subchannel drivers need to
> manually remove the uevent suppression and generate an ADD uevent as
> soon as they are sure that the subchannel will stay around. This misses
> out on all uevents that are not the initial ADD uevent that would be
> generated while uevents are suppressed; for example, all subchannels
> were missing the BIND uevent.
>
> As uevents being generated even for I/O subchannels without an
> operational device turned out to be not as bad as missing uevents and
> complicating the code flow, let's remove uevent suppression for
> subchannel
s/subchannel/subchannels./
>
> Signed-off-by: Vineeth Vijayan <vneethv@xxxxxxxxxxxxx>
> [cohuck@xxxxxxxxxx: modified changelog]
> ---
> drivers/s390/cio/chsc_sch.c | 5 -----
> drivers/s390/cio/css.c | 19 -------------------
> drivers/s390/cio/device.c | 18 ------------------
> drivers/s390/cio/eadm_sch.c | 5 -----
> drivers/s390/cio/vfio_ccw_drv.c | 5 -----
> 5 files changed, 52 deletions(-)
(...)
> @@ -1035,16 +1027,6 @@ static int io_subchannel_probe(struct subchannel *sch)
> "attributes for subchannel "
> "0.%x.%04x (rc=%d)\n",
> sch->schid.ssid, sch->schid.sch_no, rc);
> - /*
> - * The console subchannel already has an associated ccw_device.
> - * Throw the delayed uevent for the subchannel, register
> - * the ccw_device and exit.
Maybe keep at least part of this comment?
/*
* The console subchannel already has an associated ccw_device.
* Register it and exit.
*/
> - */
> - if (dev_get_uevent_suppress(&sch->dev)) {
> - /* should always be the case for the console */
> - dev_set_uevent_suppress(&sch->dev, 0);
> - kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
> - }
> cdev = sch_get_cdev(sch);
> rc = device_add(&cdev->dev);
> if (rc) {
Otherwise looks good to me.
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
