mm: Don't use __vma_adjust() in __split_vma()

Use the abstracted locking and maple tree operations.  Since
__split_vma() is the only user of the __vma_adjust() function to use the
insert argument, drop that argument.  Remove the NULL passed through
from fs/exec's shift_arg_pages() at the same time.

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

diff --git a/fs/exec.c b/fs/exec.c
index 9843cecd031a7126daa325a909423d934c61396f..a52175a559fd4f3e7a10eaf818f3ffec5c0afb36 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -702,7 +702,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
        /*
         * cover the whole range: [new_start, old_end)
         */
-       if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL))
+       if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff))
                return -ENOMEM;
 
        /*
@@ -737,7 +737,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
        /*
         * Shrink the vma to just the new range.  Always succeeds.
         */
-       vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
+       vma_adjust(vma, new_start, new_end, vma->vm_pgoff);
 
        return 0;
 }

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6dee7cd93f53ffdc1fd3313b40470f8767c9f828..0a827fae6f62d6744d9b55c07899495964661990 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2599,12 +2599,11 @@ void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
 /* mmap.c */
 extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
 extern int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
-       unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert,
-       struct vm_area_struct *expand);
+       unsigned long end, pgoff_t pgoff, struct vm_area_struct *expand);
 static inline int vma_adjust(struct vm_area_struct *vma, unsigned long start,
-       unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
+       unsigned long end, pgoff_t pgoff)
 {
-       return __vma_adjust(vma, start, end, pgoff, insert, NULL);
+       return __vma_adjust(vma, start, end, pgoff, NULL);
 }
 extern struct vm_area_struct *vma_merge(struct mm_struct *,
        struct vm_area_struct *prev, unsigned long addr, unsigned long end,

diff --git a/mm/mmap.c b/mm/mmap.c
index 5e4075d86b932d9341a3ef617ad015e3a3c039fa..449c0167995e78da3c4d6a7a6b75394187ea3815 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -598,7 +598,6 @@ static inline void unlock_vma(struct vma_locking *vl, struct ma_state *mas,
                 * us to insert it before dropping the locks
                 * (it may either follow vma or precede it).
                 */
-               mas_reset(mas);
                vma_mas_store(vl->insert, mas);
                mm->map_count++;
        }
@@ -720,8 +719,7 @@ nomem:
  * before we drop the necessary locks.
  */
 int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
-       unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert,
-       struct vm_area_struct *expand)
+       unsigned long end, pgoff_t pgoff, struct vm_area_struct *expand)
 {
        struct mm_struct *mm = vma->vm_mm;
        struct vm_area_struct *remove2 = NULL;
@@ -735,7 +733,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
        struct vm_area_struct *exporter = NULL, *importer = NULL;
        struct vma_locking vma_lock;
 
-       if (next && !insert) {
+       if (next) {
                if (end >= next->vm_end) {
                        /*
                         * vma expands, overlapping all the next, and
@@ -827,37 +825,28 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
 
        VM_WARN_ON(vma_lock.anon_vma && adjust_next && next->anon_vma &&
                   vma_lock.anon_vma != next->anon_vma);
-       vma_lock.insert = insert;
+
        lock_vma(&vma_lock);
 
-       if (start != vma->vm_start) {
-               if ((vma->vm_start < start) &&
-                   (!insert || (insert->vm_end != start))) {
-                       vma_mas_szero(&mas, vma->vm_start, start);
-                       VM_WARN_ON(insert && insert->vm_start > vma->vm_start);
-               } else {
-                       vma_changed = true;
-               }
-               vma->vm_start = start;
-       }
-       if (end != vma->vm_end) {
-               if (vma->vm_end > end) {
-                       if (!insert || (insert->vm_start != end)) {
-                               vma_mas_szero(&mas, end, vma->vm_end);
-                               mas_reset(&mas);
-                               VM_WARN_ON(insert &&
-                                          insert->vm_end < vma->vm_end);
-                       }
-               } else {
-                       vma_changed = true;
-               }
-               vma->vm_end = end;
+       if (vma->vm_start < start) {
+               vma_mas_szero(&mas, vma->vm_start, start);
+       } else if (start != vma->vm_start) {
+               vma_changed = true;
+       }
+
+       if (vma->vm_end > end) {
+               vma_mas_szero(&mas, end, vma->vm_end);
+       } else if (end != vma->vm_end) {
+               vma_changed = true;
        }
 
+       vma->vm_start = start;
+       vma->vm_end = end;
+       vma->vm_pgoff = pgoff;
+
        if (vma_changed)
                vma_mas_store(vma, &mas);
 
-       vma->vm_pgoff = pgoff;
        if (adjust_next) {
                next->vm_start += adjust_next;
                next->vm_pgoff += adjust_next >> PAGE_SHIFT;
@@ -1059,21 +1048,20 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
        if (merge_prev && merge_next &&
                        is_mergeable_anon_vma(prev->anon_vma,
                                next->anon_vma, NULL)) {         /* cases 1, 6 */
-               err = __vma_adjust(prev, prev->vm_start,
-                                       next->vm_end, prev->vm_pgoff, NULL,
-                                       prev);
+               err = __vma_adjust(prev, prev->vm_start, next->vm_end,
+                                  prev->vm_pgoff, prev);
                res = prev;
        } else if (merge_prev) {                        /* cases 2, 5, 7 */
-               err = __vma_adjust(prev, prev->vm_start,
-                                       end, prev->vm_pgoff, NULL, prev);
+               err = __vma_adjust(prev, prev->vm_start, end, prev->vm_pgoff,
+                                  prev);
                res = prev;
        } else if (merge_next) {
                if (prev && addr < prev->vm_end)        /* case 4 */
-                       err = __vma_adjust(prev, prev->vm_start,
-                                       addr, prev->vm_pgoff, NULL, next);
+                       err = __vma_adjust(prev, prev->vm_start, addr,
+                                          prev->vm_pgoff, next);
                else                                    /* cases 3, 8 */
                        err = __vma_adjust(mid, addr, next->vm_end,
-                                       next->vm_pgoff - pglen, NULL, next);
+                                          next->vm_pgoff - pglen, next);
                res = next;
        }
 
@@ -2203,6 +2191,8 @@ static void unmap_region(struct mm_struct *mm, struct maple_tree *mt,
 int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
                unsigned long addr, int new_below)
 {
+       MA_STATE(mas, &mm->mm_mt, 0, 0);
+       struct vma_locking vma_lock;
        struct vm_area_struct *new;
        int err;
        validate_mm_mt(mm);
@@ -2217,16 +2207,20 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
        if (!new)
                return -ENOMEM;
 
-       if (new_below)
+       err = -ENOMEM;
+       if (mas_preallocate(&mas, vma, GFP_KERNEL))
+               goto out_free_vma;
+
+       if (new_below) {
                new->vm_end = addr;
-       else {
+       } else {
                new->vm_start = addr;
                new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
        }
 
        err = vma_dup_policy(vma, new);
        if (err)
-               goto out_free_vma;
+               goto out_free_mas;
 
        err = anon_vma_clone(new, vma);
        if (err)
@@ -2238,28 +2232,27 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
        if (new->vm_ops && new->vm_ops->open)
                new->vm_ops->open(new);
 
-       if (new_below)
-               err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
-                       ((addr - new->vm_start) >> PAGE_SHIFT), new);
-       else
-               err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
+       vma_adjust_trans_huge(vma, vma->vm_start, addr, 0);
+       init_vma_lock(&vma_lock, vma);
+       vma_lock.insert = new;
+       lock_vma(&vma_lock);
 
-       /* Success. */
-       if (!err)
-               return 0;
+       if (new_below) {
+               vma->vm_start = addr;
+               vma->vm_pgoff += (addr - new->vm_start) >> PAGE_SHIFT;
+       } else {
+               vma->vm_end = addr;
+       }
 
-       /* Avoid vm accounting in close() operation */
-       new->vm_start = new->vm_end;
-       new->vm_pgoff = 0;
-       /* Clean everything up if vma_adjust failed. */
-       if (new->vm_ops && new->vm_ops->close)
-               new->vm_ops->close(new);
-       if (new->vm_file)
-               fput(new->vm_file);
-       unlink_anon_vmas(new);
- out_free_mpol:
+       /* unlock_vma stores the new vma */
+       unlock_vma(&vma_lock, &mas, mm);
+       return 0;
+
+out_free_mpol:
        mpol_put(vma_policy(new));
- out_free_vma:
+out_free_mas:
+       mas_destroy(&mas);
+out_free_vma:
        vm_area_free(new);
        validate_mm_mt(mm);
        return err;