Re: [PATCH 12/18] tools/testing/cxl: Define a fixed volatile configuration to parse

[Dan Williams <dan.j.williams@intel.com>]

Jonathan Cameron wrote:
> On Sun, 05 Feb 2023 17:03:35 -0800
> Dan Williams <dan.j.williams@intel.com> wrote:
> 
> > Take two endpoints attached to the first switch on the first host-bridge
> > in the cxl_test topology and define a pre-initialized region. This is a
> > x2 interleave underneath a x1 CXL Window.
> > 
> > $ modprobe cxl_test
> > $ # cxl list -Ru
> > {
> >   "region":"region3",
> >   "resource":"0xf010000000",
> >   "size":"512.00 MiB (536.87 MB)",
> >   "interleave_ways":2,
> >   "interleave_granularity":4096,
> >   "decode_state":"commit"
> > }
> > 
> > Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> > ---
> >  drivers/cxl/core/core.h      |    3 -
> >  drivers/cxl/core/hdm.c       |    3 +
> >  drivers/cxl/core/port.c      |    4 +
> >  drivers/cxl/cxl.h            |    4 +
> >  drivers/cxl/cxlmem.h         |    3 +
> >  tools/testing/cxl/test/cxl.c |  146 +++++++++++++++++++++++++++++++++++++++---
> >  6 files changed, 148 insertions(+), 15 deletions(-)
> > 
> 
> > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> > index 8130430ffbcf..8d0895cbae93 100644
> > --- a/drivers/cxl/core/port.c
> > +++ b/drivers/cxl/core/port.c
> > @@ -458,6 +458,7 @@ bool is_switch_decoder(struct device *dev)
> >  {
> >  	return is_root_decoder(dev) || dev->type == &cxl_decoder_switch_type;
> >  }
> > +EXPORT_SYMBOL_NS_GPL(is_switch_decoder, CXL);
> >  
> >  struct cxl_decoder *to_cxl_decoder(struct device *dev)
> >  {
> > @@ -485,6 +486,7 @@ struct cxl_switch_decoder *to_cxl_switch_decoder(struct device *dev)
> >  		return NULL;
> >  	return container_of(dev, struct cxl_switch_decoder, cxld.dev);
> >  }
> > +EXPORT_SYMBOL_NS_GPL(to_cxl_switch_decoder, CXL);
> >  
> >  static void cxl_ep_release(struct cxl_ep *ep)
> >  {
> > @@ -528,7 +530,7 @@ static const struct device_type cxl_port_type = {
> >  
> >  bool is_cxl_port(struct device *dev)
> >  {
> > -	return dev->type == &cxl_port_type;
> > +	return dev && dev->type == &cxl_port_type;
> 
> Adding that protection just for mocking seems a bit nasty.
> Could you push the sanity check out to the caller or am I missing something?
> Perhaps worth calling out the reason we'd call this on a NULL dev with a comment
> or similar.

Oh, that was probably a bug fix for an interim version of cxl_test that
I neglected to come back and clean up. A "while (port)" loop should not
walk off the top of a port->dev.parent chain.

Confirmed that the self-test still passes with this extra check gone.

> >  }
> >  EXPORT_SYMBOL_NS_GPL(is_cxl_port, CXL);
> >  
> > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> > index 9b3765c5c81a..4c6ee6c96f23 100644
> > --- a/drivers/cxl/cxl.h
> > +++ b/drivers/cxl/cxl.h
> > @@ -452,6 +452,7 @@ struct cxl_region_params {
> >   * struct cxl_region - CXL region
> >   * @dev: This region's device
> >   * @id: This region's id. Id is globally unique across all regions
> > + * @fixed: At least one decoder in this region was locked down at init
> >   * @mode: Endpoint decoder allocation / access mode
> >   * @type: Endpoint decoder target type
> >   * @cxl_nvb: nvdimm bridge for coordinating @cxlr_pmem setup / shutdown
> > @@ -462,6 +463,7 @@ struct cxl_region_params {
> >  struct cxl_region {
> >  	struct device dev;
> >  	int id;
> > +	bool fixed;
> 
> I was wondering why a mocking patch was changing the region state structure...
> It isn't - this isn't used that I can find.

Another interim hack that I failed to cleanup before posting.