[PATCH 15/35] x86, lmb: Add lmb_reserve_area_overlap_ok()

[Yinghai Lu <yinghai@kernel.org>]

Some areas from firmware could be reserved several times from different callers.

If these area are overlapped, We may have overlapped entries in lmb.reserved.

Try to free the area at first, before rerserve them again.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 arch/x86/include/asm/lmb.h |    1 +
 arch/x86/mm/lmb.c          |   18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/lmb.h b/arch/x86/include/asm/lmb.h
index dd42ac1..9329e09 100644
--- a/arch/x86/include/asm/lmb.h
+++ b/arch/x86/include/asm/lmb.h
@@ -7,6 +7,7 @@ u64 lmb_find_area_size(u64 start, u64 *sizep, u64 align);
 void lmb_to_bootmem(u64 start, u64 end);
 
 void lmb_reserve_area(u64 start, u64 end, char *name);
+void lmb_reserve_area_overlap_ok(u64 start, u64 end, char *name);
 void lmb_free_area(u64 start, u64 end);
 void lmb_add_memory(u64 start, u64 end);
 struct range;
diff --git a/arch/x86/mm/lmb.c b/arch/x86/mm/lmb.c
index 19a5f49..1100c18 100644
--- a/arch/x86/mm/lmb.c
+++ b/arch/x86/mm/lmb.c
@@ -309,6 +309,24 @@ void __init lmb_reserve_area(u64 start, u64 end, char *name)
 	lmb_add_region(&lmb.reserved, start, end - start);
 }
 
+/*
+ * Could be used to avoid having overlap entries in lmb.reserved.region.
+ *  Don't need to use it with area that is from lmb_find_area()
+ *  Only use it for the area that fw hidden area.
+ */
+void __init lmb_reserve_area_overlap_ok(u64 start, u64 end, char *name)
+{
+	if (start == end)
+		return;
+
+	if (WARN_ONCE(start > end, "lmb_reserve_area_overlap_ok: wrong range [%#llx, %#llx]\n", start, end))
+		return;
+
+	/* Free that region at first */
+	lmb_free(start, end - start);
+	lmb_add_region(&lmb.reserved, start, end - start);
+}
+
 void __init lmb_free_area(u64 start, u64 end)
 {
 	if (start == end)
-- 
1.6.4.2