percpu: reorganize chunk creation and destruction

Reorganize alloc/free_pcpu_chunk() such that chunk struct alloc/free
live in pcpu_alloc/free_chunk() and the rest in
pcpu_create/destroy_chunk().  While at it, add missing error handling
for chunk->map allocation failure.

This is to allow alternate chunk management implementation for percpu
nommu support.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Cc: Graff Yang <graff.yang@gmail.com>
Cc: Sonic Zhang <sonic.adi@gmail.com>

1 files changed, 46 insertions, 24 deletions

diff --git a/mm/percpu.c b/mm/percpu.c
index 1aeb081f30ec..105f171aad29 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -636,6 +636,38 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
         pcpu_chunk_relocate(chunk, oslot);
 }
 
+static struct pcpu_chunk *pcpu_alloc_chunk(void)
+{
+        struct pcpu_chunk *chunk;
+
+        chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL);
+        if (!chunk)
+                return NULL;
+
+        chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
+        if (!chunk->map) {
+                kfree(chunk);
+                return NULL;
+        }
+
+        chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
+        chunk->map[chunk->map_used++] = pcpu_unit_size;
+
+        INIT_LIST_HEAD(&chunk->list);
+        chunk->free_size = pcpu_unit_size;
+        chunk->contig_hint = pcpu_unit_size;
+
+        return chunk;
+}
+
+static void pcpu_free_chunk(struct pcpu_chunk *chunk)
+{
+        if (!chunk)
+                return;
+        pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
+        kfree(chunk);
+}
+
 /**
  * pcpu_get_pages_and_bitmap - get temp pages array and bitmap
  * @chunk: chunk of interest
@@ -1028,41 +1060,31 @@ err_free:
         return rc;
 }
 
-static void free_pcpu_chunk(struct pcpu_chunk *chunk)
+static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
 {
-        if (!chunk)
-                return;
-        if (chunk->vms)
+        if (chunk && chunk->vms)
                 pcpu_free_vm_areas(chunk->vms, pcpu_nr_groups);
-        pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
-        kfree(chunk);
+        pcpu_free_chunk(chunk);
 }
 
-static struct pcpu_chunk *alloc_pcpu_chunk(void)
+static struct pcpu_chunk *pcpu_create_chunk(void)
 {
         struct pcpu_chunk *chunk;
+        struct vm_struct **vms;
 
-        chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL);
+        chunk = pcpu_alloc_chunk();
         if (!chunk)
                 return NULL;
 
-        chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
-        chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
-        chunk->map[chunk->map_used++] = pcpu_unit_size;
-
-        chunk->vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
-                                       pcpu_nr_groups, pcpu_atom_size,
-                                       GFP_KERNEL);
-        if (!chunk->vms) {
-                free_pcpu_chunk(chunk);
+        vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
+                                pcpu_nr_groups, pcpu_atom_size, GFP_KERNEL);
+        if (!vms) {
+                pcpu_free_chunk(chunk);
                 return NULL;
         }
 
-        INIT_LIST_HEAD(&chunk->list);
-        chunk->free_size = pcpu_unit_size;
-        chunk->contig_hint = pcpu_unit_size;
-        chunk->base_addr = chunk->vms[0]->addr - pcpu_group_offsets[0];
-
+        chunk->vms = vms;
+        chunk->base_addr = vms[0]->addr - pcpu_group_offsets[0];
         return chunk;
 }
 
@@ -1155,7 +1177,7 @@ restart:
         /* hmmm... no space left, create a new chunk */
         spin_unlock_irqrestore(&pcpu_lock, flags);
 
-        chunk = alloc_pcpu_chunk();
+        chunk = pcpu_create_chunk();
         if (!chunk) {
                 err = "failed to allocate new chunk";
                 goto fail_unlock_mutex;
@@ -1267,7 +1289,7 @@ static void pcpu_reclaim(struct work_struct *work)
 
         list_for_each_entry_safe(chunk, next, &todo, list) {
                 pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
-                free_pcpu_chunk(chunk);
+                pcpu_destroy_chunk(chunk);
         }
 
         mutex_unlock(&pcpu_alloc_mutex);