This patch introduces the helper function for_each_mem_pfn_range_rev() for
later use.
Signed-off-by: Wei Yang <richard.weiy...@gmail.com>
---
include/linux/memblock.h | 18 ++++++++++++++++++
mm/memblock.c | 39 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 56 insertions(+), 1 deletion(-)
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 5b759c9acf97..87a0ebe18606 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -203,6 +203,8 @@ int memblock_search_pfn_nid(unsigned long pfn, unsigned
long *start_pfn,
unsigned long *end_pfn);
void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
unsigned long *out_end_pfn, int *out_nid);
+void __next_mem_pfn_range_rev(int *idx, int nid, unsigned long *out_start_pfn,
+ unsigned long *out_end_pfn, int *out_nid);
/**
* for_each_mem_pfn_range - early memory pfn range iterator
@@ -217,6 +219,22 @@ void __next_mem_pfn_range(int *idx, int nid, unsigned long
*out_start_pfn,
#define for_each_mem_pfn_range(i, nid, p_start, p_end, p_nid) \
for (i = -1, __next_mem_pfn_range(&i, nid, p_start, p_end, p_nid); \
i >= 0; __next_mem_pfn_range(&i, nid, p_start, p_end, p_nid))
+
+/**
+ * for_each_mem_pfn_range_rev - early memory pfn range rev-iterator
+ * @i: an integer used as loop variable
+ * @nid: node selector, %NUMA_NO_NODE for all nodes
+ * @p_start: ptr to ulong for start pfn of the range, can be %NULL
+ * @p_end: ptr to ulong for end pfn of the range, can be %NULL
+ * @p_nid: ptr to int for nid of the range, can be %NULL
+ *
+ * Walks over configured memory ranges in reverse order.
+ */
+#define for_each_mem_pfn_range_rev(i, nid, p_start, p_end, p_nid) \
+ for (i = (int)INT_MAX, \
+ __next_mem_pfn_range_rev(&i, nid, p_start, p_end, p_nid); \
+ i != (int)INT_MAX; \
+ __next_mem_pfn_range_rev(&i, nid, p_start, p_end, p_nid))
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
/**
diff --git a/mm/memblock.c b/mm/memblock.c
index 7608bc305936..79490005ecd6 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1075,7 +1075,7 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int
nid, ulong flags,
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
/*
- * Common iterator interface used to define for_each_mem_range().
+ * Common iterator interface used to define for_each_mem_pfn_range().
*/
void __init_memblock __next_mem_pfn_range(int *idx, int nid,
unsigned long *out_start_pfn,
@@ -1105,6 +1105,43 @@ void __init_memblock __next_mem_pfn_range(int *idx, int
nid,
*out_nid = r->nid;
}
+/*
+ * Common rev-iterator interface used to define for_each_mem_pfn_range_rev().
+ */
+void __init_memblock __next_mem_pfn_range_rev(int *idx, int nid,
+ unsigned long *out_start_pfn,
+ unsigned long *out_end_pfn, int *out_nid)
+{
+ struct memblock_type *type = &memblock.memory;
+ struct memblock_region *r;
+
+ if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is
deprecated. Use NUMA_NO_NODE instead\n"))
+ nid = NUMA_NO_NODE;
+
+ if (*idx == (int)INT_MAX)
+ *idx = type->cnt;
+
+ while (--*idx >= 0) {
+ r = &type->regions[*idx];
+
+ if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size))
+ continue;
+ if (nid == NUMA_NO_NODE || nid == r->nid)
+ break;
+ }
+ if (*idx < 0) {
+ *idx = (int)INT_MAX;
+ return;
+ }
+
+ if (out_start_pfn)
+ *out_start_pfn = PFN_UP(r->base);
+ if (out_end_pfn)
+ *out_end_pfn = PFN_DOWN(r->base + r->size);
+ if (out_nid)
+ *out_nid = r->nid;
+}
+
/**
* memblock_set_node - set node ID on memblock regions
* @base: base of area to set node ID for
--
2.11.0
