[PATCH daxctl v2 1/5] libdaxctl: add mapping iterator APIs

[Joao Martins <joao.m.martins@oracle.com>]

Add the following APIs to be able to iterate over a
dynamic device-dax mapping list, as well as fetching
each of the mapping attributes.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
 daxctl/lib/libdaxctl-private.h |  8 ++++
 daxctl/lib/libdaxctl.c         | 91 +++++++++++++++++++++++++++++++++++++++++-
 daxctl/lib/libdaxctl.sym       |  6 +++
 daxctl/libdaxctl.h             | 12 ++++++
 4 files changed, 116 insertions(+), 1 deletion(-)

diff --git a/daxctl/lib/libdaxctl-private.h b/daxctl/lib/libdaxctl-private.h
index b307a8bc9438..6d05aefbeda0 100644
--- a/daxctl/lib/libdaxctl-private.h
+++ b/daxctl/lib/libdaxctl-private.h
@@ -91,6 +91,12 @@ struct daxctl_region {
 	struct list_head devices;
 };
 
+struct daxctl_mapping {
+	struct daxctl_dev *dev;
+	unsigned long long pgoff, start, end;
+	struct list_node list;
+};
+
 struct daxctl_dev {
 	int id, major, minor;
 	void *dev_buf;
@@ -104,6 +110,8 @@ struct daxctl_dev {
 	struct daxctl_region *region;
 	struct daxctl_memory *mem;
 	int target_node;
+	int num_mappings;
+	struct list_head mappings;
 };
 
 struct daxctl_memory {
diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
index 39871427c799..3781e9ed27d5 100644
--- a/daxctl/lib/libdaxctl.c
+++ b/daxctl/lib/libdaxctl.c
@@ -526,7 +526,8 @@ static void *add_dax_dev(void *parent, int id, const char *daxdev_base)
 			free(path);
 			return dev_dup;
 		}
-
+	dev->num_mappings = -1;
+	list_head_init(&dev->mappings);
 	list_add(&region->devices, &dev->list);
 	free(path);
 	return dev;
@@ -1150,6 +1151,94 @@ DAXCTL_EXPORT unsigned long daxctl_memory_get_block_size(struct daxctl_memory *m
 	return mem->block_size;
 }
 
+static void mappings_init(struct daxctl_dev *dev)
+{
+	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
+	char buf[SYSFS_ATTR_SIZE];
+	char *path = dev->dev_buf;
+	int i;
+
+	if (dev->num_mappings != -1)
+		return;
+
+	dev->num_mappings = 0;
+	for (;;) {
+		struct daxctl_mapping *mapping;
+		unsigned long long pgoff, start, end;
+
+		i = dev->num_mappings;
+		mapping = calloc(1, sizeof(*mapping));
+		if (!mapping) {
+			err(ctx, "%s: mapping%u allocation failure\n",
+				daxctl_dev_get_devname(dev), i);
+			continue;
+		}
+
+		sprintf(path, "%s/mapping%d/start", dev->dev_path, i);
+		if (sysfs_read_attr(ctx, path, buf) < 0) {
+			free(mapping);
+			break;
+		}
+		start = strtoull(buf, NULL, 0);
+
+		sprintf(path, "%s/mapping%d/end", dev->dev_path, i);
+		if (sysfs_read_attr(ctx, path, buf) < 0) {
+			free(mapping);
+			break;
+		}
+		end = strtoull(buf, NULL, 0);
+
+		sprintf(path, "%s/mapping%d/page_offset", dev->dev_path, i);
+		if (sysfs_read_attr(ctx, path, buf) < 0) {
+			free(mapping);
+			break;
+		}
+		pgoff = strtoull(buf, NULL, 0);
+
+		mapping->dev = dev;
+		mapping->start = start;
+		mapping->end = end;
+		mapping->pgoff = pgoff;
+
+		dev->num_mappings++;
+		list_add(&dev->mappings, &mapping->list);
+	}
+}
+
+DAXCTL_EXPORT struct daxctl_mapping *daxctl_mapping_get_first(struct daxctl_dev *dev)
+{
+	mappings_init(dev);
+
+	return list_top(&dev->mappings, struct daxctl_mapping, list);
+}
+
+DAXCTL_EXPORT struct daxctl_mapping *daxctl_mapping_get_next(struct daxctl_mapping *mapping)
+{
+	struct daxctl_dev *dev = mapping->dev;
+
+	return list_next(&dev->mappings, mapping, list);
+}
+
+DAXCTL_EXPORT unsigned long long daxctl_mapping_get_start(struct daxctl_mapping *mapping)
+{
+	return mapping->start;
+}
+
+DAXCTL_EXPORT unsigned long long daxctl_mapping_get_end(struct daxctl_mapping *mapping)
+{
+	return mapping->end;
+}
+
+DAXCTL_EXPORT unsigned long long  daxctl_mapping_get_offset(struct daxctl_mapping *mapping)
+{
+	return mapping->pgoff;
+}
+
+DAXCTL_EXPORT unsigned long long daxctl_mapping_get_size(struct daxctl_mapping *mapping)
+{
+	return mapping->end - mapping->start + 1;
+}
+
 static int memblock_is_online(struct daxctl_memory *mem, char *memblock)
 {
 	struct daxctl_dev *dev = daxctl_memory_get_dev(mem);
diff --git a/daxctl/lib/libdaxctl.sym b/daxctl/lib/libdaxctl.sym
index c3d08179c9fd..08362b683678 100644
--- a/daxctl/lib/libdaxctl.sym
+++ b/daxctl/lib/libdaxctl.sym
@@ -83,4 +83,10 @@ global:
 	daxctl_region_destroy_dev;
 	daxctl_dev_get_align;
 	daxctl_dev_set_align;
+	daxctl_mapping_get_first;
+	daxctl_mapping_get_next;
+	daxctl_mapping_get_start;
+	daxctl_mapping_get_end;
+	daxctl_mapping_get_offset;
+	daxctl_mapping_get_size;
 } LIBDAXCTL_7;
diff --git a/daxctl/libdaxctl.h b/daxctl/libdaxctl.h
index b0bb5d78d357..f94a72fed85b 100644
--- a/daxctl/libdaxctl.h
+++ b/daxctl/libdaxctl.h
@@ -103,6 +103,18 @@ int daxctl_memory_online_no_movable(struct daxctl_memory *mem);
              region != NULL; \
              region = daxctl_region_get_next(region))
 
+struct daxctl_mapping;
+struct daxctl_mapping *daxctl_mapping_get_first(struct daxctl_dev *dev);
+struct daxctl_mapping *daxctl_mapping_get_next(struct daxctl_mapping *mapping);
+#define daxctl_mapping_foreach(dev, mapping) \
+        for (mapping = daxctl_mapping_get_first(dev); \
+             mapping != NULL; \
+             mapping = daxctl_mapping_get_next(mapping))
+unsigned long long daxctl_mapping_get_start(struct daxctl_mapping *mapping);
+unsigned long long daxctl_mapping_get_end(struct daxctl_mapping *mapping);
+unsigned long long  daxctl_mapping_get_offset(struct daxctl_mapping *mapping);
+unsigned long long daxctl_mapping_get_size(struct daxctl_mapping *mapping);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
-- 
1.8.3.1
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