mm: use helper functions for allocating and freeing vm_area structs

The vm_area_struct is one of the most fundamental memory management
objects, but the management of it is entirely open-coded evertwhere,
ranging from allocation and freeing (using kmem_cache_[z]alloc and
kmem_cache_free) to initializing all the fields.

We want to unify this in order to end up having some unified
initialization of the vmas, and the first step to this is to at least
have basic allocation functions.

Right now those functions are literally just wrappers around the
kmem_cache_*() calls.  This is a purely mechanical conversion:

    # new vma:
    kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc()

    # copy old vma
    kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old)

    # free vma
    kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma)

to the point where the old vma passed in to the vm_area_dup() function
isn't even used yet (because I've left all the old manual initialization
alone).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 11 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index 5801b5f0a634..4286ad2dd1f5 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -182,7 +182,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
         if (vma->vm_file)
                 fput(vma->vm_file);
         mpol_put(vma_policy(vma));
-        kmem_cache_free(vm_area_cachep, vma);
+        vm_area_free(vma);
         return next;
 }
 
@@ -911,7 +911,7 @@ again:
                         anon_vma_merge(vma, next);
                 mm->map_count--;
                 mpol_put(vma_policy(next));
-                kmem_cache_free(vm_area_cachep, next);
+                vm_area_free(next);
                 /*
                  * In mprotect's case 6 (see comments on vma_merge),
                  * we must remove another next too. It would clutter
@@ -1729,7 +1729,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
          * specific mapper. the address has already been validated, but
          * not unmapped, but the maps are removed from the list.
          */
-        vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+        vma = vm_area_alloc();
         if (!vma) {
                 error = -ENOMEM;
                 goto unacct_error;
@@ -1832,7 +1832,7 @@ allow_write_and_free_vma:
         if (vm_flags & VM_DENYWRITE)
                 allow_write_access(file);
 free_vma:
-        kmem_cache_free(vm_area_cachep, vma);
+        vm_area_free(vma);
 unacct_error:
         if (charged)
                 vm_unacct_memory(charged);
@@ -2620,7 +2620,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
                         return err;
         }
 
-        new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+        new = vm_area_dup(vma);
         if (!new)
                 return -ENOMEM;
 
@@ -2669,7 +2669,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
  out_free_mpol:
         mpol_put(vma_policy(new));
  out_free_vma:
-        kmem_cache_free(vm_area_cachep, new);
+        vm_area_free(new);
         return err;
 }
 
@@ -2984,7 +2984,7 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
         /*
          * create a vma struct for an anonymous mapping
          */
-        vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+        vma = vm_area_alloc();
         if (!vma) {
                 vm_unacct_memory(len >> PAGE_SHIFT);
                 return -ENOMEM;
@@ -3202,7 +3202,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
                 }
                 *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
         } else {
-                new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+                new_vma = vm_area_dup(vma);
                 if (!new_vma)
                         goto out;
                 *new_vma = *vma;
@@ -3226,7 +3226,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 out_free_mempol:
         mpol_put(vma_policy(new_vma));
 out_free_vma:
-        kmem_cache_free(vm_area_cachep, new_vma);
+        vm_area_free(new_vma);
 out:
         return NULL;
 }
@@ -3350,7 +3350,7 @@ static struct vm_area_struct *__install_special_mapping(
         int ret;
         struct vm_area_struct *vma;
 
-        vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+        vma = vm_area_alloc();
         if (unlikely(vma == NULL))
                 return ERR_PTR(-ENOMEM);
 
@@ -3376,7 +3376,7 @@ static struct vm_area_struct *__install_special_mapping(
         return vma;
 
 out:
-        kmem_cache_free(vm_area_cachep, vma);
+        vm_area_free(vma);
         return ERR_PTR(ret);
 }