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

arch/x86/kernel/setup.c

@@ -363,20 +363,6 @@ static void __init relocate_initrd(void)
 		ramdisk_here, ramdisk_here + ramdisk_size - 1);
 }
 
-static u64 __init get_mem_size(unsigned long limit_pfn)
-{
-	int i;
-	u64 mapped_pages = 0;
-	unsigned long start_pfn, end_pfn;
-
-	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
-		start_pfn = min_t(unsigned long, start_pfn, limit_pfn);
-		end_pfn = min_t(unsigned long, end_pfn, limit_pfn);
-		mapped_pages += end_pfn - start_pfn;
-	}
-
-	return mapped_pages << PAGE_SHIFT;
-}
 static void __init early_reserve_initrd(void)
 {
 	/* Assume only end is not page aligned */
@@ -404,7 +390,7 @@ static void __init reserve_initrd(void)
 
 	initrd_start = 0;
 
-	mapped_size = get_mem_size(max_pfn_mapped);
+	mapped_size = memblock_mem_size(max_pfn_mapped);
 	if (ramdisk_size >= (mapped_size>>1))
 		panic("initrd too large to handle, "
 		       "disabling initrd (%lld needed, %lld available)\n",

include/linux/memblock.h

@@ -155,6 +155,7 @@ phys_addr_t memblock_alloc_base(phys_addr_t size, phys_addr_t align,
 phys_addr_t __memblock_alloc_base(phys_addr_t size, phys_addr_t align,
 				  phys_addr_t max_addr);
 phys_addr_t memblock_phys_mem_size(void);
+phys_addr_t memblock_mem_size(unsigned long limit_pfn);
 phys_addr_t memblock_start_of_DRAM(void);
 phys_addr_t memblock_end_of_DRAM(void);
 void memblock_enforce_memory_limit(phys_addr_t memory_limit);

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)
 {