Stop creating cxl_dax during cxl_region_probe(). Early DAX registration can online memory before ownership of Soft Reserved ranges is finalized. This makes it difficult to tear down regions later when HMEM determines that a region should not claim that range.
Introduce a register_dax flag in struct cxl_region_params and gate DAX registration on this flag. Leave probe time registration disabled for regions discovered during early CXL enumeration; set the flag only for regions created dynamically at runtime to preserve existing behaviour. This patch prepares the region code for later changes where cxl_dax setup occurs from the HMEM path only after ownership arbitration completes. Signed-off-by: Smita Koralahalli <[email protected]> --- drivers/cxl/core/region.c | 21 ++++++++++++++++----- drivers/cxl/cxl.h | 1 + 2 files changed, 17 insertions(+), 5 deletions(-) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 94dbbd6b5513..c17cd8706b9d 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -2540,9 +2540,11 @@ static int cxl_region_calculate_adistance(struct notifier_block *nb, static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd, int id, enum cxl_partition_mode mode, - enum cxl_decoder_type type) + enum cxl_decoder_type type, + bool register_dax) { struct cxl_port *port = to_cxl_port(cxlrd->cxlsd.cxld.dev.parent); + struct cxl_region_params *p; struct cxl_region *cxlr; struct device *dev; int rc; @@ -2553,6 +2555,9 @@ static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd, cxlr->mode = mode; cxlr->type = type; + p = &cxlr->params; + p->register_dax = register_dax; + dev = &cxlr->dev; rc = dev_set_name(dev, "region%d", id); if (rc) @@ -2593,7 +2598,8 @@ static ssize_t create_ram_region_show(struct device *dev, } static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd, - enum cxl_partition_mode mode, int id) + enum cxl_partition_mode mode, int id, + bool register_dax) { int rc; @@ -2615,7 +2621,8 @@ static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd, return ERR_PTR(-EBUSY); } - return devm_cxl_add_region(cxlrd, id, mode, CXL_DECODER_HOSTONLYMEM); + return devm_cxl_add_region(cxlrd, id, mode, CXL_DECODER_HOSTONLYMEM, + register_dax); } static ssize_t create_region_store(struct device *dev, const char *buf, @@ -2629,7 +2636,7 @@ static ssize_t create_region_store(struct device *dev, const char *buf, if (rc != 1) return -EINVAL; - cxlr = __create_region(cxlrd, mode, id); + cxlr = __create_region(cxlrd, mode, id, true); if (IS_ERR(cxlr)) return PTR_ERR(cxlr); @@ -3523,7 +3530,7 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, do { cxlr = __create_region(cxlrd, cxlds->part[part].mode, - atomic_read(&cxlrd->region_id)); + atomic_read(&cxlrd->region_id), false); } while (IS_ERR(cxlr) && PTR_ERR(cxlr) == -EBUSY); if (IS_ERR(cxlr)) { @@ -3930,6 +3937,10 @@ static int cxl_region_probe(struct device *dev) p->res->start, p->res->end, cxlr, is_system_ram) > 0) return 0; + + if (!p->register_dax) + return 0; + return devm_cxl_add_dax_region(cxlr); default: dev_dbg(&cxlr->dev, "unsupported region mode: %d\n", diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index af78c9fd37f2..324220596890 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -495,6 +495,7 @@ struct cxl_region_params { struct cxl_endpoint_decoder *targets[CXL_DECODER_MAX_INTERLEAVE]; int nr_targets; resource_size_t cache_size; + bool register_dax; }; enum cxl_partition_mode { -- 2.17.1
