mm/mmap: convert brk to use vma iterator

Use the vma iterator API for the brk() system call.  This will provide
type safety at compile time.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>

diff --git a/mm/mmap.c b/mm/mmap.c
index 2def55555e05f10336802ae2f09c6a77a39e7e51..06707e9ae4c9116cee1f209128f11f2e4c5c02ac 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -162,10 +162,10 @@ static int check_brk_limits(unsigned long addr, unsigned long len)
 
        return mlock_future_check(current->mm, current->mm->def_flags, len);
 }
-static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
+static int do_brk_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
                         unsigned long newbrk, unsigned long oldbrk,
                         struct list_head *uf);
-static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *brkvma,
+static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *brkvma,
                unsigned long addr, unsigned long request, unsigned long flags);
 SYSCALL_DEFINE1(brk, unsigned long, brk)
 {
@@ -176,7 +176,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
        bool populate;
        bool downgraded = false;
        LIST_HEAD(uf);
-       MA_STATE(mas, &mm->mm_mt, 0, 0);
+       struct vma_iterator vmi;
 
        if (mmap_write_lock_killable(mm))
                return -EINTR;
@@ -224,8 +224,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
                int ret;
 
                /* Search one past newbrk */
-               mas_set(&mas, newbrk);
-               brkvma = mas_find(&mas, oldbrk);
+               vma_iter_init(&vmi, mm, newbrk);
+               brkvma = vma_find(&vmi, oldbrk);
                BUG_ON(brkvma == NULL);
                if (brkvma->vm_start >= oldbrk)
                        goto out; /* mapping intersects with an existing non-brk vma. */
@@ -235,7 +235,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
                 * before calling do_brk_munmap().
                 */
                mm->brk = brk;
-               ret = do_brk_munmap(&mas, brkvma, newbrk, oldbrk, &uf);
+               ret = do_brk_munmap(&vmi, brkvma, newbrk, oldbrk, &uf);
                if (ret == 1)  {
                        downgraded = true;
                        goto success;
@@ -253,14 +253,14 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
         * Only check if the next VMA is within the stack_guard_gap of the
         * expansion area
         */
-       mas_set(&mas, oldbrk);
-       next = mas_find(&mas, newbrk - 1 + PAGE_SIZE + stack_guard_gap);
+       vma_iter_init(&vmi, mm, oldbrk);
+       next = vma_find(&vmi, newbrk + PAGE_SIZE + stack_guard_gap);
        if (next && newbrk + PAGE_SIZE > vm_start_gap(next))
                goto out;
 
-       brkvma = mas_prev(&mas, mm->start_brk);
+       brkvma = vma_prev_limit(&vmi, mm->start_brk);
        /* Ok, looks good - let it rip. */
-       if (do_brk_flags(&mas, brkvma, oldbrk, newbrk - oldbrk, 0) < 0)
+       if (do_brk_flags(&vmi, brkvma, oldbrk, newbrk - oldbrk, 0) < 0)
                goto out;
 
        mm->brk = brk;
@@ -2886,7 +2886,7 @@ out:
 
 /*
  * brk_munmap() - Unmap a parital vma.
- * @mas: The maple tree state.
+ * @vmi: The vma iterator
  * @vma: The vma to be modified
  * @newbrk: the start of the address to unmap
  * @oldbrk: The end of the address to unmap
@@ -2896,7 +2896,7 @@ out:
  * unmaps a partial VMA mapping.  Does not handle alignment, downgrades lock if
  * possible.
  */
-static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
+static int do_brk_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
                         unsigned long newbrk, unsigned long oldbrk,
                         struct list_head *uf)
 {
@@ -2904,14 +2904,14 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
        int ret;
 
        arch_unmap(mm, newbrk, oldbrk);
-       ret = do_mas_align_munmap(mas, vma, mm, newbrk, oldbrk, uf, true);
+       ret = do_mas_align_munmap(&vmi->mas, vma, mm, newbrk, oldbrk, uf, true);
        validate_mm_mt(mm);
        return ret;
 }
 
 /*
  * do_brk_flags() - Increase the brk vma if the flags match.
- * @mas: The maple tree state.
+ * @vmi: The vma iterator
  * @addr: The start address
  * @len: The length of the increase
  * @vma: The vma,
@@ -2921,7 +2921,7 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
  * do not match then create a new anonymous VMA.  Eventually we may be able to
  * do some brk-specific accounting here.
  */
-static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,
+static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
                unsigned long addr, unsigned long len, unsigned long flags)
 {
        struct mm_struct *mm = current->mm;
@@ -2948,8 +2948,7 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,
        if (vma &&
            (!vma->anon_vma || list_is_singular(&vma->anon_vma_chain)) &&
            ((vma->vm_flags & ~VM_SOFTDIRTY) == flags)) {
-               mas_set_range(mas, vma->vm_start, addr + len - 1);
-               if (mas_preallocate(mas, vma, GFP_KERNEL))
+               if (vma_iter_prealloc(vmi, vma))
                        return -ENOMEM;
 
                vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0);
@@ -2959,7 +2958,7 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,
                }
                vma->vm_end = addr + len;
                vma->vm_flags |= VM_SOFTDIRTY;
-               mas_store_prealloc(mas, vma);
+               vma_iter_store(vmi, vma);
 
                if (vma->anon_vma) {
                        anon_vma_interval_tree_post_update_vma(vma);
@@ -2980,8 +2979,8 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,
        vma->vm_pgoff = addr >> PAGE_SHIFT;
        vma->vm_flags = flags;
        vma->vm_page_prot = vm_get_page_prot(flags);
-       mas_set_range(mas, vma->vm_start, addr + len - 1);
-       if (mas_store_gfp(mas, vma, GFP_KERNEL))
+       mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1);
+       if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL))
                goto mas_store_fail;
 
        mm->map_count++;
@@ -3010,7 +3009,7 @@ int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)
        int ret;
        bool populate;
        LIST_HEAD(uf);
-       MA_STATE(mas, &mm->mm_mt, addr, addr);
+       VMA_ITERATOR(vmi, mm, addr);
 
        len = PAGE_ALIGN(request);
        if (len < request)
@@ -3029,17 +3028,17 @@ int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)
        if (ret)
                goto limits_failed;
 
-       ret = do_mas_munmap(&mas, mm, addr, len, &uf, 0);
+       ret = do_mas_munmap(&vmi.mas, mm, addr, len, &uf, 0);
        if (ret)
                goto munmap_failed;
 
-       vma = mas_prev(&mas, 0);
+       vma = vma_prev(&vmi);
        if (!vma || vma->vm_end != addr || vma_policy(vma) ||
            !can_vma_merge_after(vma, flags, NULL, NULL,
                                 addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL))
                vma = NULL;
 
-       ret = do_brk_flags(&mas, vma, addr, len, flags);
+       ret = do_brk_flags(&vmi, vma, addr, len, flags);
        populate = ((mm->def_flags & VM_LOCKED) != 0);
        mmap_write_unlock(mm);
        userfaultfd_unmap_complete(mm, &uf);