memblock: Implement memblock_is_memory and memblock_is_region_memory

To make it fast, we steal ARM's binary search for memblock_is_memory()
and we use that to also the replace existing implementation of
memblock_is_reserved().

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 34 insertions, 8 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index 6f407ccf604e..aa88c62bce7f 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -487,17 +487,43 @@ void __init memblock_enforce_memory_limit(u64 memory_limit)
         }
 }
 
+static int memblock_search(struct memblock_type *type, u64 addr)
+{
+        unsigned int left = 0, right = type->cnt;
+
+        do {
+                unsigned int mid = (right + left) / 2;
+
+                if (addr < type->regions[mid].base)
+                        right = mid;
+                else if (addr >= (type->regions[mid].base +
+                                  type->regions[mid].size))
+                        left = mid + 1;
+                else
+                        return mid;
+        } while (left < right);
+        return -1;
+}
+
 int __init memblock_is_reserved(u64 addr)
 {
-        int i;
+        return memblock_search(&memblock.reserved, addr) != -1;
+}
 
-        for (i = 0; i < memblock.reserved.cnt; i++) {
-                u64 upper = memblock.reserved.regions[i].base +
-                        memblock.reserved.regions[i].size - 1;
-                if ((addr >= memblock.reserved.regions[i].base) && (addr <= upper))
-                        return 1;
-        }
-        return 0;
+int memblock_is_memory(u64 addr)
+{
+        return memblock_search(&memblock.memory, addr) != -1;
+}
+
+int memblock_is_region_memory(u64 base, u64 size)
+{
+        int idx = memblock_search(&memblock.reserved, base);
+
+        if (idx == -1)
+                return 0;
+        return memblock.reserved.regions[idx].base <= base &&
+                (memblock.reserved.regions[idx].base +
+                 memblock.reserved.regions[idx].size) >= (base + size);
 }
 
 int memblock_is_region_reserved(u64 base, u64 size)