vmalloc: implement vm_area_register_early()

Impact: allow multiple early vm areas

There are places where kernel VM area needs to be allocated before
vmalloc is initialized.  This is done by allocating static vm_struct,
initializing several fields and linking it to vmlist and later vmalloc
initialization picking up these from vmlist.  This is currently done
manually and if there's more than one such areas, there's no defined
way to arbitrate who gets which address.

This patch implements vm_area_register_early(), which takes vm_area
struct with flags and size initialized, assigns address to it and puts
it on the vmlist.  This way, multiple early vm areas can determine
which addresses they should use.  The only current user - alpha mm
init - is converted to use it.

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 13 insertions, 7 deletions

diff --git a/arch/alpha/mm/init.c b/arch/alpha/mm/init.c
index 5d7a16eab312..df6df025ded4 100644
--- a/arch/alpha/mm/init.c
+++ b/arch/alpha/mm/init.c
@@ -189,9 +189,21 @@ callback_init(void * kernel_end)
 
         if (alpha_using_srm) {
                 static struct vm_struct console_remap_vm;
-                unsigned long vaddr = VMALLOC_START;
+                unsigned long nr_pages = 0;
+                unsigned long vaddr;
                 unsigned long i, j;
 
+                /* calculate needed size */
+                for (i = 0; i < crb->map_entries; ++i)
+                        nr_pages += crb->map[i].count;
+
+                /* 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);
+
+                vaddr = (unsigned long)consle_remap_vm.addr;
+
                 /* Set up the third level PTEs and update the virtual
                    addresses of the CRB entries.  */
                 for (i = 0; i < crb->map_entries; ++i) {
@@ -213,12 +225,6 @@ callback_init(void * kernel_end)
                                 vaddr += PAGE_SIZE;
                         }
                 }
-
-                /* Let vmalloc know that we've allocated some space.  */
-                console_remap_vm.flags = VM_ALLOC;
-                console_remap_vm.addr = (void *) VMALLOC_START;
-                console_remap_vm.size = vaddr - VMALLOC_START;
-                vmlist = &console_remap_vm;
         }
 
         callback_init_done = 1;