Jonathan Cameron wrote:
> On Sun, 05 Feb 2023 17:03:02 -0800
> Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>
> > Region autodiscovery is the process of kernel creating 'struct
> > cxl_region' object to represent active CXL memory ranges it finds
> > already active in hardware when the driver loads. Typically this happens
> > when platform firmware establishes CXL memory regions and then publishes
> > them in the memory map. However, this can also happen in the case of
> > kexec-reboot after the kernel has created regions.
> >
> > In the autodiscovery case the region creation process starts with a
> > known endpoint decoder. Refactor attach_target() into a helper that is
> > suitable to be called from either sysfs, for runtime region creation, or
> > from cxl_port_probe() after it has enumerated all endpoint decoders.
> >
> > The cxl_port_probe() context is an async device-core probing context, so
> > it is not appropriate to allow SIGTERM to interrupt the assembly
> > process. Refactor attach_target() to take @cxled and @state as arguments
> > where @state indicates whether waiting from the region rwsem is
> > interruptible or not.
>
[..]
> > @@ -1418,31 +1418,25 @@ void cxl_decoder_kill_region(struct cxl_endpoint_decoder *cxled)
> > up_write(&cxl_region_rwsem);
> > }
> >
> > -static int attach_target(struct cxl_region *cxlr, const char *decoder, int pos)
> > +static int attach_target(struct cxl_region *cxlr,
> > + struct cxl_endpoint_decoder *cxled, int pos,
> > + unsigned int state)
> > {
> > - struct device *dev;
> > - int rc;
> > -
> > - dev = bus_find_device_by_name(&cxl_bus_type, NULL, decoder);
> > - if (!dev)
> > - return -ENODEV;
> > -
> > - if (!is_endpoint_decoder(dev)) {
> > - put_device(dev);
> > - return -EINVAL;
> > - }
> > + int rc = 0;
> >
> > - rc = down_write_killable(&cxl_region_rwsem);
> > + if (state == TASK_INTERRUPTIBLE)
> > + rc = down_write_killable(&cxl_region_rwsem);
> > + else
> > + down_write(&cxl_region_rwsem);
>
> I'd be tempted to do this in two hops for patch readability. First
> make the code reorg then follow up with this bit before the use
> of it in the next patch.
>
Sure.
