Add helper functions for onlining and offlining memory ranges:
- dax_kmem_do_online(): online memory with specified type (MMOP_ONLINE
or MMOP_ONLINE_MOVABLE) using online_memory_range()
- dax_kmem_do_offline(): offline memory using offline_memory()
These helpers use the memory hotplug APIs from the memory_hotplug
refactoring and will be used by the upcoming sysfs interface to allow
userspace control over memory state transitions.
No functional change as these helpers are not called yet.
Signed-off-by: Gregory Price <[email protected]>
---
drivers/dax/kmem.c | 103 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 103 insertions(+)
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 5225f2bf0b2a..30429f2d5a67 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -190,6 +190,109 @@ static int dax_kmem_do_hotremove(struct dev_dax *dev_dax,
}
#endif /* CONFIG_MEMORY_HOTREMOVE */
+/**
+ * dax_kmem_do_online - online memory blocks for dax kmem device
+ * @dev_dax: the dev_dax instance
+ * @data: the dax_kmem_data structure with resource tracking
+ * @online_type: MMOP_ONLINE or MMOP_ONLINE_MOVABLE
+ *
+ * Onlines all ranges in the dev_dax region with the specified online type.
+ * On partial failure, previously onlined ranges are rolled back to offline.
+ *
+ * Returns 0 on success, negative error code on failure.
+ */
+static int dax_kmem_do_online(struct dev_dax *dev_dax,
+ struct dax_kmem_data *data, int online_type)
+{
+ int i, j, rc;
+
+ for (i = 0; i < dev_dax->nr_range; i++) {
+ struct range range;
+
+ rc = dax_kmem_range(dev_dax, i, &range);
+ if (rc)
+ continue;
+
+ if (!data->res[i])
+ continue;
+
+ rc = online_memory_range(range.start, range_len(&range),
+ online_type);
+ if (rc)
+ goto rollback;
+ }
+
+ return 0;
+
+rollback:
+ /* Rollback previously onlined ranges */
+ for (j = 0; j < i; j++) {
+ struct range range;
+
+ if (dax_kmem_range(dev_dax, j, &range))
+ continue;
+
+ if (!data->res[j])
+ continue;
+
+ /* Best effort rollback - ignore failures */
+ offline_memory(range.start, range_len(&range));
+ }
+ return rc;
+}
+
+/**
+ * dax_kmem_do_offline - offline memory blocks for dax kmem device
+ * @dev_dax: the dev_dax instance
+ * @data: the dax_kmem_data structure with resource tracking
+ *
+ * Offlines all ranges in the dev_dax region.
+ * On partial failure, previously offlined ranges are rolled back to online.
+ *
+ * Returns 0 on success, negative error code on failure.
+ */
+static int dax_kmem_do_offline(struct dev_dax *dev_dax,
+ struct dax_kmem_data *data)
+{
+ int i, j, rc;
+
+ for (i = 0; i < dev_dax->nr_range; i++) {
+ struct range range;
+
+ rc = dax_kmem_range(dev_dax, i, &range);
+ if (rc)
+ continue;
+
+ if (!data->res[i])
+ continue;
+
+ rc = offline_memory(range.start, range_len(&range));
+ if (rc)
+ goto rollback;
+ }
+
+ return 0;
+
+rollback:
+ /*
+ * Rollback previously offlined ranges. Use MMOP_ONLINE as a safe
+ * default - the original online type is not tracked per-range.
+ */
+ for (j = 0; j < i; j++) {
+ struct range range;
+
+ if (dax_kmem_range(dev_dax, j, &range))
+ continue;
+
+ if (!data->res[j])
+ continue;
+
+ /* Best effort rollback - ignore failures */
+ online_memory_range(range.start, range_len(&range),
MMOP_ONLINE);
+ }
+ return rc;
+}
+
static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
{
struct device *dev = &dev_dax->dev;
--
2.52.0
