1 files changed, 102 insertions, 2 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index e5f3f9bdc311..0787790b1ce0 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -11,6 +11,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/bitops.h>
 #include <linux/poison.h>
@@ -18,12 +19,23 @@
 
 struct memblock memblock;
 
-static int memblock_debug;
+static int memblock_debug, memblock_can_resize;
 static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS + 1];
 static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS + 1];
 
 #define MEMBLOCK_ERROR  (~(phys_addr_t)0)
 
+/* inline so we don't get a warning when pr_debug is compiled out */
+static inline const char *memblock_type_name(struct memblock_type *type)
+{
+        if (type == &memblock.memory)
+                return "memory";
+        else if (type == &memblock.reserved)
+                return "reserved";
+        else
+                return "unknown";
+}
+
 /*
  * Address comparison utilities
  */
@@ -156,6 +168,79 @@ static void memblock_coalesce_regions(struct memblock_type *type,
         memblock_remove_region(type, r2);
 }
 
+/* Defined below but needed now */
+static long memblock_add_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size);
+
+static int memblock_double_array(struct memblock_type *type)
+{
+        struct memblock_region *new_array, *old_array;
+        phys_addr_t old_size, new_size, addr;
+        int use_slab = slab_is_available();
+
+        /* We don't allow resizing until we know about the reserved regions
+         * of memory that aren't suitable for allocation
+         */
+        if (!memblock_can_resize)
+                return -1;
+
+        pr_debug("memblock: %s array full, doubling...", memblock_type_name(type));
+
+        /* Calculate new doubled size */
+        old_size = type->max * sizeof(struct memblock_region);
+        new_size = old_size << 1;
+
+        /* Try to find some space for it.
+         *
+         * WARNING: We assume that either slab_is_available() and we use it or
+         * we use MEMBLOCK for allocations. That means that this is unsafe to use
+         * when bootmem is currently active (unless bootmem itself is implemented
+         * on top of MEMBLOCK which isn't the case yet)
+         *
+         * This should however not be an issue for now, as we currently only
+         * call into MEMBLOCK while it's still active, or much later when slab is
+         * active for memory hotplug operations
+         */
+        if (use_slab) {
+                new_array = kmalloc(new_size, GFP_KERNEL);
+                addr = new_array == NULL ? MEMBLOCK_ERROR : __pa(new_array);
+        } else
+                addr = memblock_find_base(new_size, sizeof(phys_addr_t), MEMBLOCK_ALLOC_ACCESSIBLE);
+        if (addr == MEMBLOCK_ERROR) {
+                pr_err("memblock: Failed to double %s array from %ld to %ld entries !\n",
+                       memblock_type_name(type), type->max, type->max * 2);
+                return -1;
+        }
+        new_array = __va(addr);
+
+        /* Found space, we now need to move the array over before
+         * we add the reserved region since it may be our reserved
+         * array itself that is full.
+         */
+        memcpy(new_array, type->regions, old_size);
+        memset(new_array + type->max, 0, old_size);
+        old_array = type->regions;
+        type->regions = new_array;
+        type->max <<= 1;
+
+        /* If we use SLAB that's it, we are done */
+        if (use_slab)
+                return 0;
+
+        /* Add the new reserved region now. Should not fail ! */
+        BUG_ON(memblock_add_region(&memblock.reserved, addr, new_size) < 0);
+
+        /* If the array wasn't our static init one, then free it. We only do
+         * that before SLAB is available as later on, we don't know whether
+         * to use kfree or free_bootmem_pages(). Shouldn't be a big deal
+         * anyways
+         */
+        if (old_array != memblock_memory_init_regions &&
+            old_array != memblock_reserved_init_regions)
+                memblock_free(__pa(old_array), old_size);
+
+        return 0;
+}
+
 static long memblock_add_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size)
 {
         unsigned long coalesced = 0;
@@ -196,7 +281,11 @@ static long memblock_add_region(struct memblock_type *type, phys_addr_t base, ph
 
         if (coalesced)
                 return coalesced;
-        if (type->cnt >= type->max)
+
+        /* If we are out of space, we fail. It's too late to resize the array
+         * but then this shouldn't have happened in the first place.
+         */
+        if (WARN_ON(type->cnt >= type->max))
                 return -1;
 
         /* Couldn't coalesce the MEMBLOCK, so add it to the sorted table. */
@@ -217,6 +306,14 @@ static long memblock_add_region(struct memblock_type *type, phys_addr_t base, ph
         }
         type->cnt++;
 
+        /* The array is full ? Try to resize it. If that fails, we undo
+         * our allocation and return an error
+         */
+        if (type->cnt == type->max && memblock_double_array(type)) {
+                type->cnt--;
+                return -1;
+        }
+
         return 0;
 }
 
@@ -541,6 +638,9 @@ void __init memblock_analyze(void)
 
         for (i = 0; i < memblock.memory.cnt; i++)
                 memblock.memory_size += memblock.memory.regions[i].size;
+
+        /* We allow resizing from there */
+        memblock_can_resize = 1;
 }
 
 void __init memblock_init(void)