memblock: Add memblock_mem_size()

Use it to get mem size under the limit_pfn.
to replace local version in x86 reserved_initrd.

-v2: remove not needed cast that is pointed out by HPA.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-29-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index 88adc8afb610..b8d9147e5c08 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -828,6 +828,23 @@ phys_addr_t __init memblock_phys_mem_size(void)
         return memblock.memory.total_size;
 }
 
+phys_addr_t __init memblock_mem_size(unsigned long limit_pfn)
+{
+        unsigned long pages = 0;
+        struct memblock_region *r;
+        unsigned long start_pfn, end_pfn;
+
+        for_each_memblock(memory, r) {
+                start_pfn = memblock_region_memory_base_pfn(r);
+                end_pfn = memblock_region_memory_end_pfn(r);
+                start_pfn = min_t(unsigned long, start_pfn, limit_pfn);
+                end_pfn = min_t(unsigned long, end_pfn, limit_pfn);
+                pages += end_pfn - start_pfn;
+        }
+
+        return (phys_addr_t)pages << PAGE_SHIFT;
+}
+
 /* lowest address */
 phys_addr_t __init_memblock memblock_start_of_DRAM(void)
 {