memblock: Reimplement __memblock_remove() using memblock_isolate_range()

__memblock_remove()'s open coded region manipulation can be trivially
replaced with memblock_islate_range().  This increases code sharing
and eases improving region tracking.

This pulls memblock_isolate_range() out of HAVE_MEMBLOCK_NODE_MAP.
Make it use memblock_get_region_node() instead of assuming rgn->nid is
available.

-v2: Fixed build failure on !HAVE_MEMBLOCK_NODE_MAP caused by direct
     rgn->nid access.

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

1 files changed, 9 insertions, 47 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index a1e96a0fda00..fffe68b4bf14 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -400,7 +400,6 @@ int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size)
         return memblock_add_region(&memblock.memory, base, size);
 }
 
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 /**
  * memblock_isolate_range - isolate given range into disjoint memblocks
  * @type: memblock type to isolate range for
@@ -449,7 +448,7 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
                         rgn->base = base;
                         rgn->size = rend - rgn->base;
                         memblock_insert_region(type, i, rbase, base - rbase,
-                                               rgn->nid);
+                                               memblock_get_region_node(rgn));
                 } else if (rend > end) {
                         /*
                          * @rgn intersects from above.  Split and redo the
@@ -458,7 +457,7 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
                         rgn->base = end;
                         rgn->size = rend - rgn->base;
                         memblock_insert_region(type, i--, rbase, end - rbase,
-                                               rgn->nid);
+                                               memblock_get_region_node(rgn));
                 } else {
                         /* @rgn is fully contained, record it */
                         if (!*end_rgn)
@@ -469,56 +468,19 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
 
         return 0;
 }
-#endif
 
 static int __init_memblock __memblock_remove(struct memblock_type *type,
                                              phys_addr_t base, phys_addr_t size)
 {
-        phys_addr_t end = base + size;
-        int i;
-
-        /* Walk through the array for collisions */
-        for (i = 0; i < type->cnt; i++) {
-                struct memblock_region *rgn = &type->regions[i];
-                phys_addr_t rend = rgn->base + rgn->size;
-
-                /* Nothing more to do, exit */
-                if (rgn->base > end || rgn->size == 0)
-                        break;
-
-                /* If we fully enclose the block, drop it */
-                if (base <= rgn->base && end >= rend) {
-                        memblock_remove_region(type, i--);
-                        continue;
-                }
-
-                /* If we are fully enclosed within a block
-                 * then we need to split it and we are done
-                 */
-                if (base > rgn->base && end < rend) {
-                        rgn->size = base - rgn->base;
-                        if (!memblock_add_region(type, end, rend - end))
-                                return 0;
-                        /* Failure to split is bad, we at least
-                         * restore the block before erroring
-                         */
-                        rgn->size = rend - rgn->base;
-                        WARN_ON(1);
-                        return -1;
-                }
-
-                /* Check if we need to trim the bottom of a block */
-                if (rgn->base < end && rend > end) {
-                        rgn->size -= end - rgn->base;
-                        rgn->base = end;
-                        break;
-                }
+        int start_rgn, end_rgn;
+        int i, ret;
 
-                /* And check if we need to trim the top of a block */
-                if (base < rend)
-                        rgn->size -= rend - base;
+        ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
+        if (ret)
+                return ret;
 
-        }
+        for (i = end_rgn - 1; i >= start_rgn; i--)
+                memblock_remove_region(type, i);
         return 0;
 }