mm: make vm_area_alloc() initialize core fields

Like vm_area_dup(), it initializes the anon_vma_chain head, and the
basic mm pointer.

The rest of the fields end up being different for different users,
although the plan is to also initialize the 'vm_ops' field to a dummy
entry.

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

7 files changed, 17 insertions, 26 deletions

diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index e859246badca..46bff1661836 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -2278,17 +2278,15 @@ pfm_smpl_buffer_alloc(struct task_struct *task, struct file *filp, pfm_context_t
         DPRINT(("smpl_buf @%p\n", smpl_buf));
 
         /* allocate vma */
-        vma = vm_area_alloc();
+        vma = vm_area_alloc(mm);
         if (!vma) {
                 DPRINT(("Cannot allocate vma\n"));
                 goto error_kmem;
         }
-        INIT_LIST_HEAD(&vma->anon_vma_chain);
 
         /*
          * partially initialize the vma for the sampling buffer
          */
-        vma->vm_mm           = mm;
         vma->vm_file         = get_file(filp);
         vma->vm_flags        = VM_READ|VM_MAYREAD|VM_DONTEXPAND|VM_DONTDUMP;
         vma->vm_page_prot    = PAGE_READONLY; /* XXX may need to change */
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 3f2321bffb72..bdb14a369137 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -114,10 +114,8 @@ ia64_init_addr_space (void)
          * the problem.  When the process attempts to write to the register backing store
          * for the first time, it will get a SEGFAULT in this case.
          */
-        vma = vm_area_alloc();
+        vma = vm_area_alloc(current->mm);
         if (vma) {
-                INIT_LIST_HEAD(&vma->anon_vma_chain);
-                vma->vm_mm = current->mm;
                 vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
                 vma->vm_end = vma->vm_start + PAGE_SIZE;
                 vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
@@ -133,10 +131,8 @@ ia64_init_addr_space (void)
 
         /* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
         if (!(current->personality & MMAP_PAGE_ZERO)) {
-                vma = vm_area_alloc();
+                vma = vm_area_alloc(current->mm);
                 if (vma) {
-                        INIT_LIST_HEAD(&vma->anon_vma_chain);
-                        vma->vm_mm = current->mm;
                         vma->vm_end = PAGE_SIZE;
                         vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
                         vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
diff --git a/fs/exec.c b/fs/exec.c
index 9bd83989ea25..72e961a62adb 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -290,7 +290,7 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
         struct vm_area_struct *vma = NULL;
         struct mm_struct *mm = bprm->mm;
 
-        bprm->vma = vma = vm_area_alloc();
+        bprm->vma = vma = vm_area_alloc(mm);
         if (!vma)
                 return -ENOMEM;
 
@@ -298,7 +298,6 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
                 err = -EINTR;
                 goto err_free;
         }
-        vma->vm_mm = mm;
 
         /*
          * Place the stack at the largest stack address the architecture
@@ -311,7 +310,6 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
         vma->vm_start = vma->vm_end - PAGE_SIZE;
         vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
         vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
-        INIT_LIST_HEAD(&vma->anon_vma_chain);
 
         err = insert_vm_struct(mm, vma);
         if (err)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index de2fd86c6154..d3a3842316b8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -155,7 +155,7 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
  * mmap() functions).
  */
 
-struct vm_area_struct *vm_area_alloc(void);
+struct vm_area_struct *vm_area_alloc(struct mm_struct *);
 struct vm_area_struct *vm_area_dup(struct vm_area_struct *);
 void vm_area_free(struct vm_area_struct *);
 
diff --git a/kernel/fork.c b/kernel/fork.c
index 67253e41bfb0..a191c05e757d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -308,9 +308,15 @@ static struct kmem_cache *vm_area_cachep;
 /* SLAB cache for mm_struct structures (tsk->mm) */
 static struct kmem_cache *mm_cachep;
 
-struct vm_area_struct *vm_area_alloc(void)
+struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
 {
-        return kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+        struct vm_area_struct *vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+
+        if (vma) {
+                vma->vm_mm = mm;
+                INIT_LIST_HEAD(&vma->anon_vma_chain);
+        }
+        return vma;
 }
 
 struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
diff --git a/mm/mmap.c b/mm/mmap.c
index b0ed8ce1b67e..ff1944d8d458 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1729,19 +1729,17 @@ 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 = vm_area_alloc();
+        vma = vm_area_alloc(mm);
         if (!vma) {
                 error = -ENOMEM;
                 goto unacct_error;
         }
 
-        vma->vm_mm = mm;
         vma->vm_start = addr;
         vma->vm_end = addr + len;
         vma->vm_flags = vm_flags;
         vma->vm_page_prot = vm_get_page_prot(vm_flags);
         vma->vm_pgoff = pgoff;
-        INIT_LIST_HEAD(&vma->anon_vma_chain);
 
         if (file) {
                 if (vm_flags & VM_DENYWRITE) {
@@ -2979,14 +2977,12 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
         /*
          * create a vma struct for an anonymous mapping
          */
-        vma = vm_area_alloc();
+        vma = vm_area_alloc(mm);
         if (!vma) {
                 vm_unacct_memory(len >> PAGE_SHIFT);
                 return -ENOMEM;
         }
 
-        INIT_LIST_HEAD(&vma->anon_vma_chain);
-        vma->vm_mm = mm;
         vma->vm_start = addr;
         vma->vm_end = addr + len;
         vma->vm_pgoff = pgoff;
@@ -3343,12 +3339,10 @@ static struct vm_area_struct *__install_special_mapping(
         int ret;
         struct vm_area_struct *vma;
 
-        vma = vm_area_alloc();
+        vma = vm_area_alloc(mm);
         if (unlikely(vma == NULL))
                 return ERR_PTR(-ENOMEM);
 
-        INIT_LIST_HEAD(&vma->anon_vma_chain);
-        vma->vm_mm = mm;
         vma->vm_start = addr;
         vma->vm_end = addr + len;
 
diff --git a/mm/nommu.c b/mm/nommu.c
index c2560e9cc803..1d22fdbf7d7c 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1204,7 +1204,7 @@ unsigned long do_mmap(struct file *file,
         if (!region)
                 goto error_getting_region;
 
-        vma = vm_area_alloc();
+        vma = vm_area_alloc(current->mm);
         if (!vma)
                 goto error_getting_vma;
 
@@ -1212,7 +1212,6 @@ unsigned long do_mmap(struct file *file,
         region->vm_flags = vm_flags;
         region->vm_pgoff = pgoff;
 
-        INIT_LIST_HEAD(&vma->anon_vma_chain);
         vma->vm_flags = vm_flags;
         vma->vm_pgoff = pgoff;