1 files changed, 27 insertions, 26 deletions

diff --git a/mm/percpu.c b/mm/percpu.c
index 9531590e6b69..503ccad091af 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -93,9 +93,6 @@ static size_t pcpu_chunk_struct_size __read_mostly;
 void *pcpu_base_addr __read_mostly;
 EXPORT_SYMBOL_GPL(pcpu_base_addr);
 
-/* the size of kernel static area */
-static int pcpu_static_size __read_mostly;
-
 /*
  * One mutex to rule them all.
  *
@@ -316,15 +313,28 @@ static int pcpu_split_block(struct pcpu_chunk *chunk, int i, int head, int tail)
 
         /* reallocation required? */
         if (chunk->map_alloc < target) {
-                int new_alloc = chunk->map_alloc;
+                int new_alloc;
                 int *new;
 
+                new_alloc = PCPU_DFL_MAP_ALLOC;
                 while (new_alloc < target)
                         new_alloc *= 2;
 
-                new = pcpu_realloc(chunk->map,
-                                   chunk->map_alloc * sizeof(new[0]),
-                                   new_alloc * sizeof(new[0]));
+                if (chunk->map_alloc < PCPU_DFL_MAP_ALLOC) {
+                        /*
+                         * map_alloc smaller than the default size
+                         * indicates that the chunk is one of the
+                         * first chunks and still using static map.
+                         * Allocate a dynamic one and copy.
+                         */
+                        new = pcpu_realloc(NULL, 0, new_alloc * sizeof(new[0]));
+                        if (new)
+                                memcpy(new, chunk->map,
+                                       chunk->map_alloc * sizeof(new[0]));
+                } else
+                        new = pcpu_realloc(chunk->map,
+                                           chunk->map_alloc * sizeof(new[0]),
+                                           new_alloc * sizeof(new[0]));
                 if (!new)
                         return -ENOMEM;
 
@@ -367,22 +377,6 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
         int max_contig = 0;
         int i, off;
 
-        /*
-         * The static chunk initially doesn't have map attached
-         * because kmalloc wasn't available during init.  Give it one.
-         */
-        if (unlikely(!chunk->map)) {
-                chunk->map = pcpu_realloc(NULL, 0,
-                                PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
-                if (!chunk->map)
-                        return -ENOMEM;
-
-                chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
-                chunk->map[chunk->map_used++] = -pcpu_static_size;
-                if (chunk->free_size)
-                        chunk->map[chunk->map_used++] = chunk->free_size;
-        }
-
         for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) {
                 bool is_last = i + 1 == chunk->map_used;
                 int head, tail;
@@ -874,12 +868,14 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
                                      pcpu_populate_pte_fn_t populate_pte_fn)
 {
         static struct vm_struct first_vm;
+        static int smap[2];
         struct pcpu_chunk *schunk;
         unsigned int cpu;
         int nr_pages;
         int err, i;
 
         /* santiy checks */
+        BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC);
         BUG_ON(!static_size);
         BUG_ON(!unit_size && dyn_size);
         BUG_ON(unit_size && unit_size < static_size + dyn_size);
@@ -893,7 +889,6 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
                 pcpu_unit_pages = max_t(int, PCPU_MIN_UNIT_SIZE >> PAGE_SHIFT,
                                         PFN_UP(static_size));
 
-        pcpu_static_size = static_size;
         pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
         pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size;
         pcpu_chunk_struct_size = sizeof(struct pcpu_chunk)
@@ -912,14 +907,20 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
         schunk = alloc_bootmem(pcpu_chunk_struct_size);
         INIT_LIST_HEAD(&schunk->list);
         schunk->vm = &first_vm;
+        schunk->map = smap;
+        schunk->map_alloc = ARRAY_SIZE(smap);
 
         if (dyn_size)
                 schunk->free_size = dyn_size;
         else
-                schunk->free_size = pcpu_unit_size - pcpu_static_size;
+                schunk->free_size = pcpu_unit_size - static_size;
 
         schunk->contig_hint = schunk->free_size;
 
+        schunk->map[schunk->map_used++] = -static_size;
+        if (schunk->free_size)
+                schunk->map[schunk->map_used++] = schunk->free_size;
+
         /* allocate vm address */
         first_vm.flags = VM_ALLOC;
         first_vm.size = pcpu_chunk_size;
@@ -948,7 +949,7 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
                         *pcpu_chunk_pagep(schunk, cpu, i) = page;
                 }
 
-                BUG_ON(i < PFN_UP(pcpu_static_size));
+                BUG_ON(i < PFN_UP(static_size));
 
                 if (nr_pages < 0)
                         nr_pages = i;