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() and mremap() at the same time.

Link: https://lkml.kernel.org/r/20230120162650.984577-44-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/exec.c b/fs/exec.c
index 76ee62e1d3f1b773b687fad3d6c40e9373001a12..d52fca2dd30b435ce0825abd552cab53beb1c47a 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -699,7 +699,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
        /*
         * cover the whole range: [new_start, old_end)
         */
-       if (vma_adjust(&vmi, vma, new_start, old_end, vma->vm_pgoff, NULL))
+       if (vma_adjust(&vmi, vma, new_start, old_end, vma->vm_pgoff))
                return -ENOMEM;
 
        /*
@@ -733,7 +733,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
 
        vma_prev(&vmi);
        /* Shrink the vma to just the new range */
-       return vma_adjust(&vmi, vma, new_start, new_end, vma->vm_pgoff, NULL);
+       return vma_adjust(&vmi, vma, new_start, new_end, vma->vm_pgoff);
 }
 
 /*

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2e95287a9f74452f294ed61bbce881315edfd0fe..3845de5d258132cb016577bac59ae9304f29b3ce 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2832,13 +2832,12 @@ 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 vma_iterator *vmi, 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 vma_iterator *vmi,
        struct vm_area_struct *vma, unsigned long start, unsigned long end,
-       pgoff_t pgoff, struct vm_area_struct *insert)
+       pgoff_t pgoff)
 {
-       return __vma_adjust(vmi, vma, start, end, pgoff, insert, NULL);
+       return __vma_adjust(vmi, vma, start, end, pgoff, NULL);
 }
 extern struct vm_area_struct *vma_merge(struct vma_iterator *vmi,
        struct mm_struct *, struct vm_area_struct *prev, unsigned long addr,

diff --git a/mm/mmap.c b/mm/mmap.c
index e259b33fcb525adab8f29b00f346b6ed172b2ffa..3d08d7d243f050fad8bd90baa4ee203f25d3ede5 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -691,7 +691,7 @@ nomem:
  */
 int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma,
        unsigned long start, unsigned long end, pgoff_t pgoff,
-       struct vm_area_struct *insert, struct vm_area_struct *expand)
+       struct vm_area_struct *expand)
 {
        struct mm_struct *mm = vma->vm_mm;
        struct vm_area_struct *remove2 = NULL;
@@ -704,7 +704,7 @@ int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma,
        struct vm_area_struct *exporter = NULL, *importer = NULL;
        struct vma_prepare vma_prep;
 
-       if (next && !insert) {
+       if (next) {
                if (end >= next->vm_end) {
                        /*
                         * vma expands, overlapping all the next, and
@@ -795,39 +795,25 @@ int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma,
        VM_WARN_ON(vma_prep.anon_vma && adjust_next && next->anon_vma &&
                   vma_prep.anon_vma != next->anon_vma);
 
-       vma_prep.insert = insert;
        vma_prepare(&vma_prep);
 
-       if (start != vma->vm_start) {
-               if (vma->vm_start < start) {
-                       if (!insert || (insert->vm_end != start)) {
-                               vma_iter_clear(vmi, vma->vm_start, start);
-                               vma_iter_set(vmi, 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_iter_clear(vmi, end, vma->vm_end);
-                               vma_iter_set(vmi, vma->vm_end);
-                               VM_WARN_ON(insert &&
-                                          insert->vm_end < vma->vm_end);
-                       }
-               } else {
-                       vma_changed = true;
-               }
-               vma->vm_end = end;
-       }
+       if (vma->vm_start < start)
+               vma_iter_clear(vmi, vma->vm_start, start);
+       else if (start != vma->vm_start)
+               vma_changed = true;
+
+       if (vma->vm_end > end)
+               vma_iter_clear(vmi, 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_iter_store(vmi, vma);
 
-       vma->vm_pgoff = pgoff;
        if (adjust_next) {
                next->vm_start += adjust_next;
                next->vm_pgoff += adjust_next >> PAGE_SHIFT;
@@ -846,9 +832,9 @@ int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma,
  * per-vma resources, so we don't attempt to merge those.
  */
 static inline int is_mergeable_vma(struct vm_area_struct *vma,
-                               struct file *file, unsigned long vm_flags,
-                               struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
-                               struct anon_vma_name *anon_name)
+                                  struct file *file, unsigned long vm_flags,
+                                  struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
+                                  struct anon_vma_name *anon_name)
 {
        /*
         * VM_SOFTDIRTY should not prevent from VMA merging, if we
@@ -1030,20 +1016,19 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
                        is_mergeable_anon_vma(prev->anon_vma,
                                next->anon_vma, NULL)) {         /* cases 1, 6 */
                err = __vma_adjust(vmi, prev, prev->vm_start,
-                                       next->vm_end, prev->vm_pgoff, NULL,
-                                       prev);
+                                       next->vm_end, prev->vm_pgoff, prev);
                res = prev;
        } else if (merge_prev) {                        /* cases 2, 5, 7 */
                err = __vma_adjust(vmi, prev, prev->vm_start,
-                                       end, prev->vm_pgoff, NULL, prev);
+                                       end, prev->vm_pgoff, prev);
                res = prev;
        } else if (merge_next) {
                if (prev && addr < prev->vm_end)        /* case 4 */
                        err = __vma_adjust(vmi, prev, prev->vm_start,
-                                       addr, prev->vm_pgoff, NULL, next);
+                                       addr, prev->vm_pgoff, next);
                else                                    /* cases 3, 8 */
                        err = __vma_adjust(vmi, mid, addr, next->vm_end,
-                                       next->vm_pgoff - pglen, NULL, next);
+                                       next->vm_pgoff - pglen, next);
                res = next;
        }
 
@@ -2187,11 +2172,15 @@ static void unmap_region(struct mm_struct *mm, struct maple_tree *mt,
 int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
                unsigned long addr, int new_below)
 {
+       struct vma_prepare vp;
        struct vm_area_struct *new;
        int err;
 
        validate_mm_mt(vma->vm_mm);
 
+       WARN_ON(vma->vm_start >= addr);
+       WARN_ON(vma->vm_end <= addr);
+
        if (vma->vm_ops && vma->vm_ops->may_split) {
                err = vma->vm_ops->may_split(vma, addr);
                if (err)
@@ -2202,16 +2191,20 @@ int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
        if (!new)
                return -ENOMEM;
 
-       if (new_below)
+       err = -ENOMEM;
+       if (vma_iter_prealloc(vmi))
+               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_vmi;
 
        err = anon_vma_clone(new, vma);
        if (err)
@@ -2223,33 +2216,32 @@ int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
        if (new->vm_ops && new->vm_ops->open)
                new->vm_ops->open(new);
 
-       if (new_below)
-               err = vma_adjust(vmi, vma, addr, vma->vm_end,
-                       vma->vm_pgoff + ((addr - new->vm_start) >> PAGE_SHIFT),
-                       new);
-       else
-               err = vma_adjust(vmi, vma, vma->vm_start, addr, vma->vm_pgoff,
-                                new);
+       vma_adjust_trans_huge(vma, vma->vm_start, addr, 0);
+       init_vma_prep(&vp, vma);
+       vp.insert = new;
+       vma_prepare(&vp);
 
-       /* Success. */
-       if (!err) {
-               if (new_below)
-                       vma_next(vmi);
-               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:
+       /* vma_complete stores the new vma */
+       vma_complete(&vp, vmi, vma->vm_mm);
+
+       /* Success. */
+       if (new_below)
+               vma_next(vmi);
+       validate_mm_mt(vma->vm_mm);
+       return 0;
+
+out_free_mpol:
        mpol_put(vma_policy(new));
- out_free_vma:
+out_free_vmi:
+       vma_iter_free(vmi);
+out_free_vma:
        vm_area_free(new);
        validate_mm_mt(vma->vm_mm);
        return err;

diff --git a/mm/mremap.c b/mm/mremap.c
index 6c7f49ab7d197b90abe7ad2b563b0540c55f705a..b98185f48ba5fe8f94f0c60b024f7ac4383e2dfe 100644 (file)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1054,7 +1054,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
                                        vma->vm_file, extension_pgoff, vma_policy(vma),
                                        vma->vm_userfaultfd_ctx, anon_vma_name(vma));
                        } else if (vma_adjust(&vmi, vma, vma->vm_start,
-                                       addr + new_len, vma->vm_pgoff, NULL)) {
+                                       addr + new_len, vma->vm_pgoff)) {
                                vma = NULL;
                        }
                        if (!vma) {