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Before determining how much DPA to >>>> allocate the amount of available HPA must be determined. Also, not all >>>> HPA is created equal, some specifically targets RAM, some target PMEM, >>>> some is prepared for device-memory flows like HDM-D and HDM-DB, and some >>>> is host-only (HDM-H). >>>> >>>> Wrap all of those concerns into an API that retrieves a root decoder >>>> (platform CXL window) that fits the specified constraints and the >>>> capacity available for a new region. >>>> >>>> Add a complementary function for releasing the reference to such root >>>> decoder. >>>> >>>> Based on https://lore.kernel.org/linux-cxl/168592159290.1948938.13522227102445462976.stgit@dwillia2-xfh.jf.intel.com/ >>>> >>>> Signed-off-by: Alejandro Lucero >>> One trivial comment inline. >>> >>> Reviewed-by: Jonathan Cameron >>> >>>> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c >>>> index 80caaf14d08a..0a9eab4f8e2e 100644 >>>> --- a/drivers/cxl/core/region.c >>>> +++ b/drivers/cxl/core/region.c >>>> +static int find_max_hpa(struct device *dev, void *data) >>>> +{ >>>> + struct cxlrd_max_context *ctx = data; >>>> + struct cxl_switch_decoder *cxlsd; >>>> + struct cxl_root_decoder *cxlrd; >>>> + struct resource *res, *prev; >>>> + struct cxl_decoder *cxld; >>>> + resource_size_t max; >>>> + int found = 0; >>>> + >>>> + if (!is_root_decoder(dev)) >>>> + return 0; >>>> + >>>> + cxlrd = to_cxl_root_decoder(dev); >>>> + cxlsd = &cxlrd->cxlsd; >>>> + cxld = &cxlsd->cxld; >>>> + >>>> + /* >>>> + * None flags are declared as bitmaps but for the sake of better code >>> None? >> >> Not sure you refer to syntax or semantics here. Assuming is the former: > Just the wording of the comment. I'm not sure what it means. Ok. I just want to make clear those flags fields used in the bitmap_subset are not declared as bitmaps, just in case someone points this out. I do not think this is problematic, and a good idea you gave me, but better to comment on it before someone complains about it. > >> >> No flags fields? > Not following that either. >> >>> >>>> + * used here as such, restricting the bitmap size to those bits used by >>>> + * any Type2 device driver requester. >>>> + */ >>>