[PATCH v9 04/19] cxl/core: Enforce partition order/simplify partition calls

[Ira Weiny <ira.weiny@intel.com>]

Device partitions have an implied order which is made more complex by
the addition of a dynamic partition.

Remove the ram special case information calls in favor of generic calls
with a check ahead of time to ensure the preservation of the implied
partition order.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
 drivers/cxl/core/hdm.c    | 11 ++++++++++-
 drivers/cxl/core/memdev.c | 32 +++++++++-----------------------
 drivers/cxl/cxl.h         |  1 +
 drivers/cxl/cxlmem.h      |  9 +++------
 drivers/cxl/mem.c         |  2 +-
 5 files changed, 24 insertions(+), 31 deletions(-)

diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index c5f8a17d00f1..92e1a24e2109 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -470,6 +470,7 @@ static const char *cxl_mode_name(enum cxl_partition_mode mode)
 int cxl_dpa_setup(struct cxl_dev_state *cxlds, const struct cxl_dpa_info *info)
 {
 	struct device *dev = cxlds->dev;
+	int i;
 
 	guard(rwsem_write)(&cxl_dpa_rwsem);
 
@@ -482,9 +483,17 @@ int cxl_dpa_setup(struct cxl_dev_state *cxlds, const struct cxl_dpa_info *info)
 		return 0;
 	}
 
+	/* Verify partitions are in expected order. */
+	for (i = 1; i < info->nr_partitions; i++) {
+		if (cxlds->part[i].mode < cxlds->part[i-1].mode) {
+			dev_err(dev, "Partition order mismatch\n");
+			return 0;
+		}
+	}
+
 	cxlds->dpa_res = DEFINE_RES_MEM(0, info->size);
 
-	for (int i = 0; i < info->nr_partitions; i++) {
+	for (i = 0; i < info->nr_partitions; i++) {
 		const struct cxl_dpa_part_info *part = &info->part[i];
 		int rc;
 
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index a16a5886d40a..9d6f8800e37a 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -75,20 +75,12 @@ static ssize_t label_storage_size_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(label_storage_size);
 
-static resource_size_t cxl_ram_size(struct cxl_dev_state *cxlds)
-{
-	/* Static RAM is only expected at partition 0. */
-	if (cxlds->part[0].mode != CXL_PARTMODE_RAM)
-		return 0;
-	return resource_size(&cxlds->part[0].res);
-}
-
 static ssize_t ram_size_show(struct device *dev, struct device_attribute *attr,
 			     char *buf)
 {
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
-	unsigned long long len = cxl_ram_size(cxlds);
+	unsigned long long len = cxl_part_size(cxlds, CXL_PARTMODE_RAM);
 
 	return sysfs_emit(buf, "%#llx\n", len);
 }
@@ -101,7 +93,7 @@ static ssize_t pmem_size_show(struct device *dev, struct device_attribute *attr,
 {
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
-	unsigned long long len = cxl_pmem_size(cxlds);
+	unsigned long long len = cxl_part_size(cxlds, CXL_PARTMODE_PMEM);
 
 	return sysfs_emit(buf, "%#llx\n", len);
 }
@@ -407,10 +399,11 @@ static struct attribute *cxl_memdev_attributes[] = {
 	NULL,
 };
 
-static struct cxl_dpa_perf *to_pmem_perf(struct cxl_dev_state *cxlds)
+static struct cxl_dpa_perf *part_perf(struct cxl_dev_state *cxlds,
+				      enum cxl_partition_mode mode)
 {
 	for (int i = 0; i < cxlds->nr_partitions; i++)
-		if (cxlds->part[i].mode == CXL_PARTMODE_PMEM)
+		if (cxlds->part[i].mode == mode)
 			return &cxlds->part[i].perf;
 	return NULL;
 }
@@ -421,7 +414,7 @@ static ssize_t pmem_qos_class_show(struct device *dev,
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 
-	return sysfs_emit(buf, "%d\n", to_pmem_perf(cxlds)->qos_class);
+	return sysfs_emit(buf, "%d\n", part_perf(cxlds, CXL_PARTMODE_PMEM)->qos_class);
 }
 
 static struct device_attribute dev_attr_pmem_qos_class =
@@ -433,20 +426,13 @@ static struct attribute *cxl_memdev_pmem_attributes[] = {
 	NULL,
 };
 
-static struct cxl_dpa_perf *to_ram_perf(struct cxl_dev_state *cxlds)
-{
-	if (cxlds->part[0].mode != CXL_PARTMODE_RAM)
-		return NULL;
-	return &cxlds->part[0].perf;
-}
-
 static ssize_t ram_qos_class_show(struct device *dev,
 				  struct device_attribute *attr, char *buf)
 {
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 
-	return sysfs_emit(buf, "%d\n", to_ram_perf(cxlds)->qos_class);
+	return sysfs_emit(buf, "%d\n", part_perf(cxlds, CXL_PARTMODE_RAM)->qos_class);
 }
 
 static struct device_attribute dev_attr_ram_qos_class =
@@ -482,7 +468,7 @@ static umode_t cxl_ram_visible(struct kobject *kobj, struct attribute *a, int n)
 {
 	struct device *dev = kobj_to_dev(kobj);
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-	struct cxl_dpa_perf *perf = to_ram_perf(cxlmd->cxlds);
+	struct cxl_dpa_perf *perf = part_perf(cxlmd->cxlds, CXL_PARTMODE_RAM);
 
 	if (a == &dev_attr_ram_qos_class.attr &&
 	    (!perf || perf->qos_class == CXL_QOS_CLASS_INVALID))
@@ -501,7 +487,7 @@ static umode_t cxl_pmem_visible(struct kobject *kobj, struct attribute *a, int n
 {
 	struct device *dev = kobj_to_dev(kobj);
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-	struct cxl_dpa_perf *perf = to_pmem_perf(cxlmd->cxlds);
+	struct cxl_dpa_perf *perf = part_perf(cxlmd->cxlds, CXL_PARTMODE_PMEM);
 
 	if (a == &dev_attr_pmem_qos_class.attr &&
 	    (!perf || perf->qos_class == CXL_QOS_CLASS_INVALID))
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index a9d42210e8a3..4bb0ff4d8f5f 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -482,6 +482,7 @@ struct cxl_region_params {
 	resource_size_t cache_size;
 };
 
+/* Modes should be in the implied DPA order */
 enum cxl_partition_mode {
 	CXL_PARTMODE_RAM,
 	CXL_PARTMODE_PMEM,
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 96d8edaa5003..a74ac2d70d8d 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -453,14 +453,11 @@ struct cxl_dev_state {
 #endif
 };
 
-static inline resource_size_t cxl_pmem_size(struct cxl_dev_state *cxlds)
+static inline resource_size_t cxl_part_size(struct cxl_dev_state *cxlds,
+					    enum cxl_partition_mode mode)
 {
-	/*
-	 * Static PMEM may be at partition index 0 when there is no static RAM
-	 * capacity.
-	 */
 	for (int i = 0; i < cxlds->nr_partitions; i++)
-		if (cxlds->part[i].mode == CXL_PARTMODE_PMEM)
+		if (cxlds->part[i].mode == mode)
 			return resource_size(&cxlds->part[i].res);
 	return 0;
 }
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 9675243bd05b..b58b915708f9 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -152,7 +152,7 @@ static int cxl_mem_probe(struct device *dev)
 		return -ENXIO;
 	}
 
-	if (cxl_pmem_size(cxlds) && IS_ENABLED(CONFIG_CXL_PMEM)) {
+	if (cxl_part_size(cxlds, CXL_PARTMODE_PMEM) && IS_ENABLED(CONFIG_CXL_PMEM)) {
 		rc = devm_cxl_add_nvdimm(parent_port, cxlmd);
 		if (rc) {
 			if (rc == -ENODEV)

-- 
2.49.0