mm: set up vma iterator for vma_iter_prealloc() calls

Set the correct limits for vma_iter_prealloc() calls so that the maple
tree can be smarter about how many nodes are needed.

Link: https://lkml.kernel.org/r/20230724183157.3939892-11-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/exec.c b/fs/exec.c
index 1a827d5..0b94843 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -701,6 +701,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
        if (vma != vma_next(&vmi))
                return -EFAULT;
 
+       vma_iter_prev_range(&vmi);
        /*
         * cover the whole range: [new_start, old_end)
         */

diff --git a/mm/internal.h b/mm/internal.h
index 2f35c0e..5a03bc4 100644 (file)
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1052,23 +1052,21 @@ static inline void vma_iter_config(struct vma_iterator *vmi,
 /*
  * VMA Iterator functions shared between nommu and mmap
  */
-static inline int vma_iter_prealloc(struct vma_iterator *vmi)
+static inline int vma_iter_prealloc(struct vma_iterator *vmi,
+               struct vm_area_struct *vma)
 {
-       return mas_preallocate(&vmi->mas, NULL, GFP_KERNEL);
+       return mas_preallocate(&vmi->mas, vma, GFP_KERNEL);
 }
 
-static inline void vma_iter_clear(struct vma_iterator *vmi,
-                                 unsigned long start, unsigned long end)
+static inline void vma_iter_clear(struct vma_iterator *vmi)
 {
-       mas_set_range(&vmi->mas, start, end - 1);
        mas_store_prealloc(&vmi->mas, NULL);
 }
 
 static inline int vma_iter_clear_gfp(struct vma_iterator *vmi,
                        unsigned long start, unsigned long end, gfp_t gfp)
 {
-       vmi->mas.index = start;
-       vmi->mas.last = end - 1;
+       __mas_set_range(&vmi->mas, start, end - 1);
        mas_store_gfp(&vmi->mas, NULL, gfp);
        if (unlikely(mas_is_err(&vmi->mas)))
                return -ENOMEM;
@@ -1105,8 +1103,7 @@ static inline void vma_iter_store(struct vma_iterator *vmi,
            ((vmi->mas.index > vma->vm_start) || (vmi->mas.last < vma->vm_start)))
                vma_iter_invalidate(vmi);
 
-       vmi->mas.index = vma->vm_start;
-       vmi->mas.last = vma->vm_end - 1;
+       __mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1);
        mas_store_prealloc(&vmi->mas, vma);
 }
 
@@ -1117,8 +1114,7 @@ static inline int vma_iter_store_gfp(struct vma_iterator *vmi,
            ((vmi->mas.index > vma->vm_start) || (vmi->mas.last < vma->vm_start)))
                vma_iter_invalidate(vmi);
 
-       vmi->mas.index = vma->vm_start;
-       vmi->mas.last = vma->vm_end - 1;
+       __mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1);
        mas_store_gfp(&vmi->mas, vma, gfp);
        if (unlikely(mas_is_err(&vmi->mas)))
                return -ENOMEM;

diff --git a/mm/mmap.c b/mm/mmap.c
index 1ddb024..3f10e70 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -397,7 +397,8 @@ static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma)
        VMA_ITERATOR(vmi, mm, 0);
        struct address_space *mapping = NULL;
 
-       if (vma_iter_prealloc(&vmi))
+       vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
+       if (vma_iter_prealloc(&vmi, vma))
                return -ENOMEM;
 
        vma_iter_store(&vmi, vma);
@@ -649,19 +650,16 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
        /* Only handles expanding */
        VM_WARN_ON(vma->vm_start < start || vma->vm_end > end);
 
-       if (vma_iter_prealloc(vmi))
+       /* Note: vma iterator must be pointing to 'start' */
+       vma_iter_config(vmi, start, end);
+       if (vma_iter_prealloc(vmi, vma))
                goto nomem;
 
        vma_prepare(&vp);
        vma_adjust_trans_huge(vma, start, end, 0);
-       /* VMA iterator points to previous, so set to start if necessary */
-       if (vma_iter_addr(vmi) != start)
-               vma_iter_set(vmi, start);
-
        vma->vm_start = start;
        vma->vm_end = end;
        vma->vm_pgoff = pgoff;
-       /* Note: mas must be pointing to the expanding VMA */
        vma_iter_store(vmi, vma);
 
        vma_complete(&vp, vmi, vma->vm_mm);
@@ -687,19 +685,19 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
 
        WARN_ON((vma->vm_start != start) && (vma->vm_end != end));
 
-       if (vma_iter_prealloc(vmi))
+       if (vma->vm_start < start)
+               vma_iter_config(vmi, vma->vm_start, start);
+       else
+               vma_iter_config(vmi, end, vma->vm_end);
+
+       if (vma_iter_prealloc(vmi, NULL))
                return -ENOMEM;
 
        init_vma_prep(&vp, vma);
        vma_prepare(&vp);
        vma_adjust_trans_huge(vma, start, end, 0);
 
-       if (vma->vm_start < start)
-               vma_iter_clear(vmi, vma->vm_start, start);
-
-       if (vma->vm_end > end)
-               vma_iter_clear(vmi, end, vma->vm_end);
-
+       vma_iter_clear(vmi);
        vma->vm_start = start;
        vma->vm_end = end;
        vma->vm_pgoff = pgoff;
@@ -973,7 +971,17 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
        if (err)
                return NULL;
 
-       if (vma_iter_prealloc(vmi))
+       if (vma_start < vma->vm_start || vma_end > vma->vm_end)
+               vma_expanded = true;
+
+       if (vma_expanded) {
+               vma_iter_config(vmi, vma_start, vma_end);
+       } else {
+               vma_iter_config(vmi, adjust->vm_start + adj_start,
+                               adjust->vm_end);
+       }
+
+       if (vma_iter_prealloc(vmi, vma))
                return NULL;
 
        init_multi_vma_prep(&vp, vma, adjust, remove, remove2);
@@ -982,8 +990,6 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
 
        vma_prepare(&vp);
        vma_adjust_trans_huge(vma, vma_start, vma_end, adj_start);
-       if (vma_start < vma->vm_start || vma_end > vma->vm_end)
-               vma_expanded = true;
 
        vma->vm_start = vma_start;
        vma->vm_end = vma_end;
@@ -1923,7 +1929,7 @@ static int expand_upwards(struct vm_area_struct *vma, unsigned long address)
        struct vm_area_struct *next;
        unsigned long gap_addr;
        int error = 0;
-       MA_STATE(mas, &mm->mm_mt, 0, 0);
+       MA_STATE(mas, &mm->mm_mt, vma->vm_start, address);
 
        if (!(vma->vm_flags & VM_GROWSUP))
                return -EFAULT;
@@ -1948,6 +1954,10 @@ static int expand_upwards(struct vm_area_struct *vma, unsigned long address)
                /* Check that both stack segments have the same anon_vma? */
        }
 
+       if (next)
+               mas_prev_range(&mas, address);
+
+       __mas_set_range(&mas, vma->vm_start, address - 1);
        if (mas_preallocate(&mas, vma, GFP_KERNEL))
                return -ENOMEM;
 
@@ -1993,7 +2003,6 @@ static int expand_upwards(struct vm_area_struct *vma, unsigned long address)
                                anon_vma_interval_tree_pre_update_vma(vma);
                                vma->vm_end = address;
                                /* Overwrite old entry in mtree. */
-                               mas_set_range(&mas, vma->vm_start, address - 1);
                                mas_store_prealloc(&mas, vma);
                                anon_vma_interval_tree_post_update_vma(vma);
                                spin_unlock(&mm->page_table_lock);
@@ -2038,6 +2047,10 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address)
                        return -ENOMEM;
        }
 
+       if (prev)
+               mas_next_range(&mas, vma->vm_start);
+
+       __mas_set_range(&mas, address, vma->vm_end - 1);
        if (mas_preallocate(&mas, vma, GFP_KERNEL))
                return -ENOMEM;
 
@@ -2084,7 +2097,6 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address)
                                vma->vm_start = address;
                                vma->vm_pgoff -= grow;
                                /* Overwrite old entry in mtree. */
-                               mas_set_range(&mas, address, vma->vm_end - 1);
                                mas_store_prealloc(&mas, vma);
                                anon_vma_interval_tree_post_update_vma(vma);
                                spin_unlock(&mm->page_table_lock);
@@ -2325,10 +2337,6 @@ int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
        if (!new)
                return -ENOMEM;
 
-       err = -ENOMEM;
-       if (vma_iter_prealloc(vmi))
-               goto out_free_vma;
-
        if (new_below) {
                new->vm_end = addr;
        } else {
@@ -2336,6 +2344,11 @@ int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
                new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
        }
 
+       err = -ENOMEM;
+       vma_iter_config(vmi, new->vm_start, new->vm_end);
+       if (vma_iter_prealloc(vmi, new))
+               goto out_free_vma;
+
        err = vma_dup_policy(vma, new);
        if (err)
                goto out_free_vmi;
@@ -2693,7 +2706,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
                vma_iter_next_range(&vmi);
        }
 
-
        /* Actually expand, if possible */
        if (vma &&
            !vma_expand(&vmi, vma, merge_start, merge_end, vm_pgoff, next)) {
@@ -2790,7 +2802,7 @@ cannot_expand:
                goto close_and_free_vma;
 
        error = -ENOMEM;
-       if (vma_iter_prealloc(&vmi))
+       if (vma_iter_prealloc(&vmi, vma))
                goto close_and_free_vma;
 
        /* Lock the VMA since it is modified after insertion into VMA tree */
@@ -3053,7 +3065,8 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
        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)) {
-               if (vma_iter_prealloc(vmi))
+               vma_iter_config(vmi, vma->vm_start, addr + len);
+               if (vma_iter_prealloc(vmi, vma))
                        goto unacct_fail;
 
                init_vma_prep(&vp, vma);
@@ -3068,6 +3081,8 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
                goto out;
        }
 
+       if (vma)
+               vma_iter_next_range(vmi);
        /* create a vma struct for an anonymous mapping */
        vma = vm_area_alloc(mm);
        if (!vma)

diff --git a/mm/nommu.c b/mm/nommu.c
index 418cc06..1fe0ee2 100644 (file)
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -583,7 +583,8 @@ static int delete_vma_from_mm(struct vm_area_struct *vma)
 {
        VMA_ITERATOR(vmi, vma->vm_mm, vma->vm_start);
 
-       if (vma_iter_prealloc(&vmi)) {
+       vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
+       if (vma_iter_prealloc(&vmi, vma)) {
                pr_warn("Allocation of vma tree for process %d failed\n",
                       current->pid);
                return -ENOMEM;
@@ -591,7 +592,7 @@ static int delete_vma_from_mm(struct vm_area_struct *vma)
        cleanup_vma_from_mm(vma);
 
        /* remove from the MM's tree and list */
-       vma_iter_clear(&vmi, vma->vm_start, vma->vm_end);
+       vma_iter_clear(&vmi);
        return 0;
 }
 /*
@@ -1054,9 +1055,6 @@ unsigned long do_mmap(struct file *file,
        if (!vma)
                goto error_getting_vma;
 
-       if (vma_iter_prealloc(&vmi))
-               goto error_vma_iter_prealloc;
-
        region->vm_usage = 1;
        region->vm_flags = vm_flags;
        region->vm_pgoff = pgoff;
@@ -1198,6 +1196,10 @@ unsigned long do_mmap(struct file *file,
 
 share:
        BUG_ON(!vma->vm_region);
+       vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
+       if (vma_iter_prealloc(&vmi, vma))
+               goto error_just_free;
+
        setup_vma_to_mm(vma, current->mm);
        current->mm->map_count++;
        /* add the VMA to the tree */
@@ -1244,14 +1246,6 @@ error_getting_region:
                        len, current->pid);
        show_mem();
        return -ENOMEM;
-
-error_vma_iter_prealloc:
-       kmem_cache_free(vm_region_jar, region);
-       vm_area_free(vma);
-       pr_warn("Allocation of vma tree for process %d failed\n", current->pid);
-       show_mem();
-       return -ENOMEM;
-
 }
 
 unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
@@ -1336,12 +1330,6 @@ int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
        if (!new)
                goto err_vma_dup;
 
-       if (vma_iter_prealloc(vmi)) {
-               pr_warn("Allocation of vma tree for process %d failed\n",
-                       current->pid);
-               goto err_vmi_preallocate;
-       }
-
        /* most fields are the same, copy all, and then fixup */
        *region = *vma->vm_region;
        new->vm_region = region;
@@ -1355,6 +1343,13 @@ int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
                region->vm_pgoff = new->vm_pgoff += npages;
        }
 
+       vma_iter_config(vmi, new->vm_start, new->vm_end);
+       if (vma_iter_prealloc(vmi, vma)) {
+               pr_warn("Allocation of vma tree for process %d failed\n",
+                       current->pid);
+               goto err_vmi_preallocate;
+       }
+
        if (new->vm_ops && new->vm_ops->open)
                new->vm_ops->open(new);