Re: [RESEND PATCH v13 2/8] cxl/mem: Read dynamic capacity configuration from the device

[Anisa Su <anisa.su887@gmail.com>]

On Fri, Sep 11, 2026 at 01:53:48AM +0100, Jonathan Cameron wrote:
> ...
> 
> > > > +	/* A DCD reports between 1 and 8 partitions */
> > > > +	if (dc_resp->avail_partition_count == 0 ||
> > > > +	    dc_resp->avail_partition_count > CXL_MAX_DC_PARTITIONS) {  
> > > 
> > > This strikes me as a compatibility issue waiting to happen.  Today the spec
> > > supports 8, but maybe in future it will support more and I'd not consider
> > > that a backwards compatibility break (which this would make it).  I'd clamp
> > > to CXL_MAX_DC_PARITIONS and maybe print with dev_info() if you see something
> > > bigger in the wild.
> > >   
> > I see... I did the below and moved it to the caller
> > cxl_dev_dc_identify() so the dev_err/dev_info messages are only printed
> > once, since the current function is called in a loop.
> > 
> > 		avail = dc_resp->avail_partition_count;
> > 		if (avail == 0) {
> > 			dev_err(dev, "Device reported no DC partitions\n");
> > 			return -EIO;
> > 		}
> > 
> > 		/* More than Linux handles is not a reason to refuse DCD */
> > 		if (avail > CXL_MAX_DC_PARTITIONS) {
> > 			dev_info(dev, "Device reported %u DC partitions, reading the first %u\n",
> > 				 avail, CXL_MAX_DC_PARTITIONS);
> > 			avail = CXL_MAX_DC_PARTITIONS;
> > 		}
> 
> Given you don't do anything with most of them I'd just do
> 
> 		avail = min(avail, CXL_MAX_DC_PARTITIONS);
> 
> and not print anything.
> 
> Thanks,
> 
> Jonathan

Makes sense. Done.

Thanks,
Anisa