[PATCH 1/3] memblock: introduce interfaces to assoicate tag and datawith reserved regions

[Jiang Liu]

Currently some subsystems use private static arrays to store information
assoicated with memory blocks allocated/reserved from memblock subsystem.
For example, dma-contiguous.c uses cma_reserved[] to store information
assoicated with allocated memory blocks.

So introduce interfaces to associate tag(type) and caller specific data
with allocated/reserved memblock regions. Users of memblock subsystem
may be simplified by using these new interfaces.

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
---
 include/linux/memblock.h |   33 ++++++++++++++++++++++++++
 mm/Kconfig               |    3 +++
 mm/memblock.c            |   58 +++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 93 insertions(+), 1 deletion(-)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index d452ee1..40dea53 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -22,6 +22,10 @@
 struct memblock_region {
 	phys_addr_t base;
 	phys_addr_t size;
+#ifdef CONFIG_HAVE_MEMBLOCK_TAG
+	void *data;
+	int tag;
+#endif
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 	int nid;
 #endif
@@ -118,6 +122,35 @@ void __next_free_mem_range_rev(u64 *idx, int nid, phys_addr_t *out_start,
 	     i != (u64)ULLONG_MAX;					\
 	     __next_free_mem_range_rev(&i, nid, p_start, p_end, p_nid))
 
+#ifdef CONFIG_HAVE_MEMBLOCK_TAG
+#define	MEMBLOCK_TAG_DEFAULT	0x0 /* default tag for bootmem allocatror */
+
+int memblock_mark_tag(phys_addr_t base, phys_addr_t size, int tag, void *data);
+void memblock_free_all_with_tag(int tag);
+
+/* Only merge regions with default tag */
+static inline bool memblock_tag_mergeable(struct memblock_region *prev,
+					  struct memblock_region *next)
+{
+	return prev->tag == MEMBLOCK_TAG_DEFAULT &&
+	       next->tag == MEMBLOCK_TAG_DEFAULT;
+}
+
+static inline void memblock_init_tag(struct memblock_region *reg)
+{
+	reg->tag = MEMBLOCK_TAG_DEFAULT;
+	reg->data = NULL;
+}
+#else /* CONFIG_HAVE_MEMBLOCK_TAG */
+static inline bool memblock_tag_mergeable(struct memblock_region *prev,
+					  struct memblock_region *next)
+{
+	return true;
+}
+
+static inline void memblock_init_tag(struct memblock_region *reg) {}
+#endif /* CONFIG_HAVE_MEMBLOCK_TAG */
+
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 int memblock_set_node(phys_addr_t base, phys_addr_t size, int nid);
 
diff --git a/mm/Kconfig b/mm/Kconfig
index a3f8ddd..5080390 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -131,6 +131,9 @@ config SPARSEMEM_VMEMMAP
 config HAVE_MEMBLOCK
 	boolean
 
+config HAVE_MEMBLOCK_TAG
+	boolean
+
 config HAVE_MEMBLOCK_NODE_MAP
 	boolean
 
diff --git a/mm/memblock.c b/mm/memblock.c
index 6259055..c2c644e 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -307,7 +307,8 @@ static void __init_memblock memblock_merge_regions(struct memblock_type *type)
 
 		if (this->base + this->size != next->base ||
 		    memblock_get_region_node(this) !=
-		    memblock_get_region_node(next)) {
+		    memblock_get_region_node(next) ||
+		    !memblock_tag_mergeable(this, next)) {
 			BUG_ON(this->base + this->size > next->base);
 			i++;
 			continue;
@@ -339,6 +340,7 @@ static void __init_memblock memblock_insert_region(struct memblock_type *type,
 	memmove(rgn + 1, rgn, (type->cnt - idx) * sizeof(*rgn));
 	rgn->base = base;
 	rgn->size = size;
+	memblock_init_tag(rgn);
 	memblock_set_region_node(rgn, nid);
 	type->cnt++;
 	type->total_size += size;
@@ -764,6 +766,60 @@ int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size,
 }
 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 
+#ifdef CONFIG_HAVE_MEMBLOCK_TAG
+/**
+ * memblock_mark_tag - mark @tag and @data with reserved regions
+ * @base: base of area to mark @tag and @data with
+ * @size: size of area to mark @tag and @data with
+ * @tag: tag (type) to assoicated with reserved regions
+ * @data: caller specific data to associated with reserved regions
+ *
+ * Associate @tag(type) and caller specific @data with reserved memblock
+ * regions in [@base,@base+@size).
+ * Regions which cross the area boundaries are split as necessary.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_mark_tag(phys_addr_t base, phys_addr_t size,
+				      int tag, void *data)
+{
+	struct memblock_type *type = &memblock.reserved;
+	int start_rgn, end_rgn;
+	int i, ret;
+
+	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
+	if (ret)
+		return ret;
+
+	for (i = start_rgn; i < end_rgn; i++) {
+		type->regions[i].tag = tag;
+		type->regions[i].data = data;
+	}
+
+	memblock_merge_regions(type);
+
+	return 0;
+}
+
+/**
+ * memblock_free_all_with_tag - free all reserved regions with @tag
+ * @tag: tag to identify reserved memblock regions to be freed
+ *
+ * Free all reserved memblock regions with tag (type) of @tag
+ */
+void __init_memblock memblock_free_all_with_tag(int tag)
+{
+	int i;
+	struct memblock_type *type = &memblock.reserved;
+
+	/* scan backward because it may remove current region */
+	for (i = type->cnt - 1; i >= 0; i--)
+		if (type->regions[i].tag == tag)
+			memblock_remove_region(type, i);
+}
+#endif /* CONFIG_HAVE_MEMBLOCK_TAG */
+
 static phys_addr_t __init memblock_alloc_base_nid(phys_addr_t size,
 					phys_addr_t align, phys_addr_t max_addr,
 					int nid)
-- 
1.7.9.5


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