memblock: Reimplement memblock_enforce_memory_limit() using __memblock_remove()

With recent updates, the basic memblock operations are robust enough
that there's no reason for memblock_enfore_memory_limit() to directly
manipulate memblock region arrays.  Reimplement it using
__memblock_remove().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>

1 files changed, 13 insertions, 29 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index 945dc31258eb..b44875f5a996 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -804,44 +804,28 @@ phys_addr_t __init_memblock memblock_end_of_DRAM(void)
 }
 
 /* You must call memblock_analyze() after this. */
-void __init memblock_enforce_memory_limit(phys_addr_t memory_limit)
+void __init memblock_enforce_memory_limit(phys_addr_t limit)
 {
         unsigned long i;
-        phys_addr_t limit;
-        struct memblock_region *p;
+        phys_addr_t max_addr = (phys_addr_t)ULLONG_MAX;
 
-        if (!memory_limit)
+        if (!limit)
                 return;
 
-        /* Truncate the memblock regions to satisfy the memory limit. */
-        limit = memory_limit;
+        /* find out max address */
         for (i = 0; i < memblock.memory.cnt; i++) {
-                if (limit > memblock.memory.regions[i].size) {
-                        limit -= memblock.memory.regions[i].size;
-                        continue;
-                }
-
-                memblock.memory.regions[i].size = limit;
-                memblock.memory.cnt = i + 1;
-                break;
-        }
-
-        memory_limit = memblock_end_of_DRAM();
+                struct memblock_region *r = &memblock.memory.regions[i];
 
-        /* And truncate any reserves above the limit also. */
-        for (i = 0; i < memblock.reserved.cnt; i++) {
-                p = &memblock.reserved.regions[i];
-
-                if (p->base > memory_limit)
-                        p->size = 0;
-                else if ((p->base + p->size) > memory_limit)
-                        p->size = memory_limit - p->base;
-
-                if (p->size == 0) {
-                        memblock_remove_region(&memblock.reserved, i);
-                        i--;
+                if (limit <= r->size) {
+                        max_addr = r->base + limit;
+                        break;
                 }
+                limit -= r->size;
         }
+
+        /* truncate both memory and reserved regions */
+        __memblock_remove(&memblock.memory, max_addr, (phys_addr_t)ULLONG_MAX);
+        __memblock_remove(&memblock.reserved, max_addr, (phys_addr_t)ULLONG_MAX);
 }
 
 static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr)