memblock: Implement for_each_free_mem_range()

Implement for_each_free_mem_range() which iterates over free memory
areas according to memblock (memory && !reserved).  This will be used
to simplify memblock users.

Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1310462166-31469-7-git-send-email-tj@kernel.org
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index c36a55d3c1c2..31def584cceb 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -61,6 +61,26 @@ extern long memblock_remove(phys_addr_t base, phys_addr_t size);
 extern long memblock_free(phys_addr_t base, phys_addr_t size);
 extern long memblock_reserve(phys_addr_t base, phys_addr_t size);
 
+extern void __next_free_mem_range(u64 *idx, int nid, phys_addr_t *out_start,
+                                  phys_addr_t *out_end, int *out_nid);
+
+/**
+ * for_each_free_mem_range - iterate through free memblock areas
+ * @i: u64 used as loop variable
+ * @nid: node selector, %MAX_NUMNODES for all nodes
+ * @p_start: ptr to phys_addr_t for start address of the range, can be %NULL
+ * @p_end: ptr to phys_addr_t for end address of the range, can be %NULL
+ * @p_nid: ptr to int for nid of the range, can be %NULL
+ *
+ * Walks over free (memory && !reserved) areas of memblock.  Available as
+ * soon as memblock is initialized.
+ */
+#define for_each_free_mem_range(i, nid, p_start, p_end, p_nid)          \
+        for (i = 0,                                                     \
+             __next_free_mem_range(&i, nid, p_start, p_end, p_nid);     \
+             i != (u64)ULLONG_MAX;                                      \
+             __next_free_mem_range(&i, nid, p_start, p_end, p_nid))
+
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 extern int memblock_set_node(phys_addr_t base, phys_addr_t size, int nid);