x86_64: fix e820_hole_size based on address ranges

e820_hole_size() now uses the newly extracted helper function,
e820_find_active_region(), to determine the size of usable RAM in a range of
PFN's.

This was previously broken because of two reasons:

 - The start and end PFN's of each e820 entry were not properly rounded
   prior to excluding those entries in the range, and

 - Entries smaller than a page were not properly excluded from being
   accumulated.

This resulted in emulated nodes being incorrectly mapped to ranges that
were completely reserved and not candidates for being registered as
active ranges.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 6 deletions

diff --git a/arch/x86_64/mm/numa.c b/arch/x86_64/mm/numa.c
index 30bf8043984d..0191b1ca6aa4 100644
--- a/arch/x86_64/mm/numa.c
+++ b/arch/x86_64/mm/numa.c
@@ -273,9 +273,6 @@ void __init numa_init_array(void)
 
 #ifdef CONFIG_NUMA_EMU
 /* Numa emulation */
-#define E820_ADDR_HOLE_SIZE(start, end)                                 \
-        (e820_hole_size((start) >> PAGE_SHIFT, (end) >> PAGE_SHIFT) <<  \
-        PAGE_SHIFT)
 char *cmdline __initdata;
 
 /*
@@ -319,7 +316,7 @@ static int __init split_nodes_equally(struct bootnode *nodes, u64 *addr,
                 return -1;
         if (num_nodes > MAX_NUMNODES)
                 num_nodes = MAX_NUMNODES;
-        size = (max_addr - *addr - E820_ADDR_HOLE_SIZE(*addr, max_addr)) /
+        size = (max_addr - *addr - e820_hole_size(*addr, max_addr)) /
                num_nodes;
         /*
          * Calculate the number of big nodes that can be allocated as a result
@@ -347,7 +344,7 @@ static int __init split_nodes_equally(struct bootnode *nodes, u64 *addr,
                 if (i == num_nodes + node_start - 1)
                         end = max_addr;
                 else
-                        while (end - *addr - E820_ADDR_HOLE_SIZE(*addr, end) <
+                        while (end - *addr - e820_hole_size(*addr, end) <
                                size) {
                                 end += FAKE_NODE_MIN_SIZE;
                                 if (end > max_addr) {
@@ -488,7 +485,6 @@ out:
         numa_init_array();
         return 0;
 }
-#undef E820_ADDR_HOLE_SIZE
 #endif /* CONFIG_NUMA_EMU */
 
 void __init numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn)