Jonathan Cameron wrote: > On Mon, 07 Oct 2024 18:16:20 -0500 > ira.weiny@xxxxxxxxx wrote: > > > From: Navneet Singh <navneet.singh@xxxxxxxxx> > > > > Endpoint decoder mode is used to represent the partition the decoder > > points to such as ram or pmem. > > > > Expand the mode to allow a decoder to point to a specific DC partition > > (Region). > > > > Signed-off-by: Navneet Singh <navneet.singh@xxxxxxxxx> > > Co-developed-by: Ira Weiny <ira.weiny@xxxxxxxxx> > > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> > > A few comments inline about ways that can make this a little tidier > and less fragile. All Done. Yea good idea on the enum. Ira [snip] > > (RW) When a CXL decoder is of devtype "cxl_decoder_endpoint" it > > translates from a host physical address range, to a device local > > address range. Device-local address ranges are further split > > - into a 'ram' (volatile memory) range and 'pmem' (persistent > > - memory) range. The 'mode' attribute emits one of 'ram', 'pmem', > > - 'mixed', or 'none'. The 'mixed' indication is for error cases > > - when a decoder straddles the volatile/persistent partition > > - boundary, and 'none' indicates the decoder is not actively > > - decoding, or no DPA allocation policy has been set. > > + into a 'ram' (volatile memory) range, 'pmem' (persistent > > + memory) range, or Dynamic Capacity (DC) range. > memory) range, and Dynamic Capacity (DC) ranges. > > (doesn't work with preceding text otherwise) > [snip] > > + if (mode >= CXL_DECODER_DC0 && mode <= CXL_DECODER_DC7) { > > + struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds); > > + > > + rc = dc_mode_to_region_index(mode); > > + if (!resource_size(&cxlds->dc_res[rc])) { > > + dev_dbg(dev, "no available dynamic capacity\n"); > > + rc = -ENXIO; > > + goto out; > Probably worth adding a precursor patch that uses guard(rwsem_write) on > the cxl_dpa_rwsem > Allows for early returns simplifying existing code and this. [snip] > > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c > > index 85b912c11f04..23b4f266a83a 100644 > > --- a/drivers/cxl/core/port.c > > +++ b/drivers/cxl/core/port.c > > @@ -205,11 +205,11 @@ static ssize_t mode_store(struct device *dev, struct device_attribute *attr, > > enum cxl_decoder_mode mode; > > ssize_t rc; > > > > - if (sysfs_streq(buf, "pmem")) > > - mode = CXL_DECODER_PMEM; > > - else if (sysfs_streq(buf, "ram")) > > - mode = CXL_DECODER_RAM; > > - else > > + for (mode = CXL_DECODER_RAM; mode < CXL_DECODER_MIXED; mode++) > > + if (sysfs_streq(buf, cxl_decoder_mode_names[mode])) > > + break; > > + > Loop over them all then do what you have here but explicit matches > to reject the ones that can't be set. > Add a MODE_COUNT to the end of the options. > > for (mode = 0; mode < CXL_DECODER_MODE_COUNT; mode++) > if (sysfs_streq(buf, cxl_decoder_mode_names[mode])) > break; > > if (mode == CXL_DECODER_MODE_COUNT) > return -EINVAL; > > if (mode == CXL_DECODER_NONE) > return -EINVAL; > > /* Not yet supported */ > if (mode == CXL_DECODER_MIXED) > return -EINVAL; > ... > > > + if (mode >= CXL_DECODER_MIXED) > > return -EINVAL; > > > > rc = cxl_dpa_set_mode(cxled, mode); > > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > > index 8b7099c38a40..cbaacbe0f36d 100644 > > --- a/drivers/cxl/cxl.h > > +++ b/drivers/cxl/cxl.h > > @@ -365,6 +365,9 @@ struct cxl_decoder { > > /* > > * CXL_DECODER_DEAD prevents endpoints from being reattached to regions > > * while cxld_unregister() is running > > + * > > + * NOTE: CXL_DECODER_RAM must be second and CXL_DECODER_MIXED must be last. > This is a bit ugly. I'd change the logic a bit to avoid it. > The list of things we don't support is short so just check for them. > See above. > [snip]