vmalloc: add @align to vm_area_register_early()

Impact: allow larger alignment for early vmalloc area allocation

Some early vmalloc users might want larger alignment, for example, for
custom large page mapping.  Add @align to vm_area_register_early().
While at it, drop docbook comment on non-existent @size.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>

4 files changed, 10 insertions, 7 deletions

diff --git a/arch/alpha/mm/init.c b/arch/alpha/mm/init.c
index df6df025ded4..91eddd8505df 100644
--- a/arch/alpha/mm/init.c
+++ b/arch/alpha/mm/init.c
@@ -200,7 +200,7 @@ callback_init(void * kernel_end)
                 /* register the vm area */
                 console_remap_vm.flags = VM_ALLOC;
                 console_remap_vm.size = nr_pages << PAGE_SHIFT;
-                vm_area_register_early(&console_remap_vm);
+                vm_area_register_early(&console_remap_vm, PAGE_SIZE);
 
                 vaddr = (unsigned long)consle_remap_vm.addr;
 
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 599ba7984310..2f6994fdf0e0 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -109,6 +109,6 @@ extern long vwrite(char *buf, char *addr, unsigned long count);
  */
 extern rwlock_t vmlist_lock;
 extern struct vm_struct *vmlist;
-extern __init void vm_area_register_early(struct vm_struct *vm);
+extern __init void vm_area_register_early(struct vm_struct *vm, size_t align);
 
 #endif /* _LINUX_VMALLOC_H */
diff --git a/mm/percpu.c b/mm/percpu.c
index ed92caa2aa3b..41e7a5f5ab1b 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -860,7 +860,7 @@ size_t __init pcpu_setup_static(pcpu_populate_pte_fn_t populate_pte_fn,
         /* init and register vm area */
         static_vm.flags = VM_ALLOC;
         static_vm.size = pcpu_chunk_size;
-        vm_area_register_early(&static_vm);
+        vm_area_register_early(&static_vm, PAGE_SIZE);
 
         /* init static_chunk */
         static_chunk = alloc_bootmem(pcpu_chunk_struct_size);
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 224eca9650a8..366ae9ea6af2 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -995,7 +995,7 @@ EXPORT_SYMBOL(vm_map_ram);
 /**
  * vm_area_register_early - register vmap area early during boot
  * @vm: vm_struct to register
- * @size: size of area to register
+ * @align: requested alignment
  *
  * This function is used to register kernel vm area before
  * vmalloc_init() is called.  @vm->size and @vm->flags should contain
@@ -1004,12 +1004,15 @@ EXPORT_SYMBOL(vm_map_ram);
  *
  * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
  */
-void __init vm_area_register_early(struct vm_struct *vm)
+void __init vm_area_register_early(struct vm_struct *vm, size_t align)
 {
         static size_t vm_init_off __initdata;
+        unsigned long addr;
+
+        addr = ALIGN(VMALLOC_START + vm_init_off, align);
+        vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
 
-        vm->addr = (void *)VMALLOC_START + vm_init_off;
-        vm_init_off = PFN_ALIGN(vm_init_off + vm->size);
+        vm->addr = (void *)addr;
 
         vm->next = vmlist;
         vmlist = vm;