The patch titled
Subject: nommu: convert nommu to using the vma iterator
has been added to the -mm mm-unstable branch. Its filename is
nommu-convert-nommu-to-using-the-vma-iterator.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/nommu-convert-nommu-to-using-the-vma-iterator.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: nommu: convert nommu to using the vma iterator
Date: Fri, 20 Jan 2023 11:26:28 -0500
Gain type safety in nommu by using the vma_iterator and not the maple tree
directly.
Link: https://lkml.kernel.org/r/20230120162650.984577-28-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/nommu.c~nommu-convert-nommu-to-using-the-vma-iterator
+++ a/mm/nommu.c
@@ -544,19 +544,6 @@ static void put_nommu_region(struct vm_r
__put_nommu_region(region);
}
-void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas)
-{
- mas_set_range(mas, vma->vm_start, vma->vm_end - 1);
- mas_store_prealloc(mas, vma);
-}
-
-void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas)
-{
- mas->index = vma->vm_start;
- mas->last = vma->vm_end - 1;
- mas_store_prealloc(mas, NULL);
-}
-
static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm)
{
vma->vm_mm = mm;
@@ -574,13 +561,13 @@ static void setup_vma_to_mm(struct vm_ar
}
/*
- * mas_add_vma_to_mm() - Maple state variant of add_mas_to_mm().
- * @mas: The maple state with preallocations.
+ * vmi_add_vma_to_mm() - VMA Iterator variant of add_vmi_to_mm().
+ * @vmi: The VMA iterator
* @mm: The mm_struct
* @vma: The vma to add
*
*/
-static void mas_add_vma_to_mm(struct ma_state *mas, struct mm_struct *mm,
+static void vmi_add_vma_to_mm(struct vma_iterator *vmi, struct mm_struct *mm,
struct vm_area_struct *vma)
{
BUG_ON(!vma->vm_region);
@@ -589,7 +576,7 @@ static void mas_add_vma_to_mm(struct ma_
mm->map_count++;
/* add the VMA to the tree */
- vma_mas_store(vma, mas);
+ vma_iter_store(vmi, vma);
}
/*
@@ -600,14 +587,14 @@ static void mas_add_vma_to_mm(struct ma_
*/
static int add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
{
- MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_end);
+ VMA_ITERATOR(vmi, mm, vma->vm_start);
- if (mas_preallocate(&mas, GFP_KERNEL)) {
+ if (vma_iter_prealloc(&vmi)) {
pr_warn("Allocation of vma tree for process %d failed\n",
current->pid);
return -ENOMEM;
}
- mas_add_vma_to_mm(&mas, mm, vma);
+ vmi_add_vma_to_mm(&vmi, mm, vma);
return 0;
}
@@ -626,14 +613,15 @@ static void cleanup_vma_from_mm(struct v
i_mmap_unlock_write(mapping);
}
}
+
/*
* delete a VMA from its owning mm_struct and address space
*/
static int delete_vma_from_mm(struct vm_area_struct *vma)
{
- MA_STATE(mas, &vma->vm_mm->mm_mt, 0, 0);
+ VMA_ITERATOR(vmi, vma->vm_mm, vma->vm_start);
- if (mas_preallocate(&mas, GFP_KERNEL)) {
+ if (vma_iter_prealloc(&vmi)) {
pr_warn("Allocation of vma tree for process %d failed\n",
current->pid);
return -ENOMEM;
@@ -641,10 +629,9 @@ static int delete_vma_from_mm(struct vm_
cleanup_vma_from_mm(vma);
/* remove from the MM's tree and list */
- vma_mas_remove(vma, &mas);
+ vma_iter_clear(&vmi, vma->vm_start, vma->vm_end);
return 0;
}
-
/*
* destroy a VMA record
*/
@@ -675,9 +662,9 @@ EXPORT_SYMBOL(find_vma_intersection);
*/
struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
{
- MA_STATE(mas, &mm->mm_mt, addr, addr);
+ VMA_ITERATOR(vmi, mm, addr);
- return mas_walk(&mas);
+ return vma_iter_load(&vmi);
}
EXPORT_SYMBOL(find_vma);
@@ -709,9 +696,9 @@ static struct vm_area_struct *find_vma_e
{
struct vm_area_struct *vma;
unsigned long end = addr + len;
- MA_STATE(mas, &mm->mm_mt, addr, addr);
+ VMA_ITERATOR(vmi, mm, addr);
- vma = mas_walk(&mas);
+ vma = vma_iter_load(&vmi);
if (!vma)
return NULL;
if (vma->vm_start != addr)
@@ -1062,7 +1049,7 @@ unsigned long do_mmap(struct file *file,
vm_flags_t vm_flags;
unsigned long capabilities, result;
int ret;
- MA_STATE(mas, ¤t->mm->mm_mt, 0, 0);
+ VMA_ITERATOR(vmi, current->mm, 0);
*populate = 0;
@@ -1091,8 +1078,8 @@ unsigned long do_mmap(struct file *file,
if (!vma)
goto error_getting_vma;
- if (mas_preallocate(&mas, GFP_KERNEL))
- goto error_maple_preallocate;
+ if (vma_iter_prealloc(&vmi))
+ goto error_vma_iter_prealloc;
region->vm_usage = 1;
region->vm_flags = vm_flags;
@@ -1234,7 +1221,7 @@ unsigned long do_mmap(struct file *file,
current->mm->total_vm += len >> PAGE_SHIFT;
share:
- mas_add_vma_to_mm(&mas, current->mm, vma);
+ vmi_add_vma_to_mm(&vmi, current->mm, vma);
/* we flush the region from the icache only when the first executable
* mapping of it is made */
@@ -1250,7 +1237,7 @@ share:
error_just_free:
up_write(&nommu_region_sem);
error:
- mas_destroy(&mas);
+ vma_iter_free(&vmi);
if (region->vm_file)
fput(region->vm_file);
kmem_cache_free(vm_region_jar, region);
@@ -1278,7 +1265,7 @@ error_getting_region:
show_free_areas(0, NULL);
return -ENOMEM;
-error_maple_preallocate:
+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);
@@ -1344,20 +1331,18 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_ar
* split a vma into two pieces at address 'addr', a new vma is allocated either
* for the first part or the tail.
*/
-int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, int new_below)
+int vmi_split_vma(struct vma_iterator *vmi, struct mm_struct *mm,
+ struct vm_area_struct *vma, unsigned long addr, int new_below)
{
struct vm_area_struct *new;
struct vm_region *region;
unsigned long npages;
- MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_end);
/* we're only permitted to split anonymous regions (these should have
* only a single usage on the region) */
if (vma->vm_file)
return -ENOMEM;
- mm = vma->vm_mm;
if (mm->map_count >= sysctl_max_map_count)
return -ENOMEM;
@@ -1369,10 +1354,10 @@ int split_vma(struct mm_struct *mm, stru
if (!new)
goto err_vma_dup;
- if (mas_preallocate(&mas, GFP_KERNEL)) {
+ if (vma_iter_prealloc(vmi)) {
pr_warn("Allocation of vma tree for process %d failed\n",
current->pid);
- goto err_mas_preallocate;
+ goto err_vmi_preallocate;
}
/* most fields are the same, copy all, and then fixup */
@@ -1406,13 +1391,11 @@ int split_vma(struct mm_struct *mm, stru
setup_vma_to_mm(vma, mm);
setup_vma_to_mm(new, mm);
- mas_set_range(&mas, vma->vm_start, vma->vm_end - 1);
- mas_store(&mas, vma);
- vma_mas_store(new, &mas);
+ vma_iter_store(vmi, new);
mm->map_count++;
return 0;
-err_mas_preallocate:
+err_vmi_preallocate:
vm_area_free(new);
err_vma_dup:
kmem_cache_free(vm_region_jar, region);
@@ -1466,7 +1449,7 @@ static int shrink_vma(struct mm_struct *
*/
int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf)
{
- MA_STATE(mas, &mm->mm_mt, start, start);
+ VMA_ITERATOR(vmi, mm, start);
struct vm_area_struct *vma;
unsigned long end;
int ret = 0;
@@ -1478,7 +1461,7 @@ int do_munmap(struct mm_struct *mm, unsi
end = start + len;
/* find the first potentially overlapping VMA */
- vma = mas_find(&mas, end - 1);
+ vma = vma_find(&vmi, end);
if (!vma) {
static int limit;
if (limit < 5) {
@@ -1497,7 +1480,7 @@ int do_munmap(struct mm_struct *mm, unsi
return -EINVAL;
if (end == vma->vm_end)
goto erase_whole_vma;
- vma = mas_next(&mas, end - 1);
+ vma = vma_find(&vmi, end);
} while (vma);
return -EINVAL;
} else {
@@ -1511,7 +1494,7 @@ int do_munmap(struct mm_struct *mm, unsi
if (end != vma->vm_end && offset_in_page(end))
return -EINVAL;
if (start != vma->vm_start && end != vma->vm_end) {
- ret = split_vma(mm, vma, start, 1);
+ ret = vmi_split_vma(&vmi, mm, vma, start, 1);
if (ret < 0)
return ret;
}
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
maple_tree-add-mas_init-function.patch
maple_tree-fix-potential-rcu-issue.patch
maple_tree-reduce-user-error-potential.patch
test_maple_tree-test-modifications-while-iterating.patch
mm-expand-vma-iterator-interface.patch
mm-mmap-convert-brk-to-use-vma-iterator.patch
kernel-fork-convert-forking-to-using-the-vmi-iterator.patch
mmap-convert-vma_link-vma-iterator.patch
mm-mmap-remove-preallocation-from-do_mas_align_munmap.patch
mmap-change-do_mas_munmap-and-do_mas_aligned_munmap-to-use-vma-iterator.patch
mmap-convert-vma_expand-to-use-vma-iterator.patch
mm-add-temporary-vma-iterator-versions-of-vma_merge-split_vma-and-__split_vma.patch
ipc-shm-use-the-vma-iterator-for-munmap-calls.patch
userfaultfd-use-vma-iterator.patch
mm-change-mprotect_fixup-to-vma-iterator.patch
mlock-convert-mlock-to-vma-iterator.patch
coredump-convert-to-vma-iterator.patch
mempolicy-convert-to-vma-iterator.patch
task_mmu-convert-to-vma-iterator.patch
sched-convert-to-vma-iterator.patch
madvise-use-vmi-iterator-for-__split_vma-and-vma_merge.patch
mmap-pass-through-vmi-iterator-to-__split_vma.patch
mmap-use-vmi-version-of-vma_merge.patch
mm-mremap-use-vmi-version-of-vma_merge.patch
nommu-convert-nommu-to-using-the-vma-iterator.patch
mm-switch-vma_merge-split_vma-and-__split_vma-to-vma-iterator.patch
mmap-convert-__vma_adjust-to-use-vma-iterator.patch
mm-pass-through-vma-iterator-to-__vma_adjust.patch
madvise-use-split_vma-instead-of-__split_vma.patch
mm-remove-unnecessary-write-to-vma-iterator-in-__vma_adjust.patch
mm-pass-vma-iterator-through-to-__vma_adjust.patch
mm-add-vma-iterator-to-vma_adjust-arguments.patch
mmap-clean-up-mmap_region-unrolling.patch
mm-change-munmap-splitting-order-and-move_vma.patch
mm-mmap-move-anon_vma-setting-in-__vma_adjust.patch
mm-mmap-refactor-locking-out-of-__vma_adjust.patch
mm-mmap-use-vma_prepare-and-vma_complete-in-vma_expand.patch
mm-mmap-introduce-init_vma_prep-and-init_multi_vma_prep.patch
mm-dont-use-__vma_adjust-in-__split_vma.patch
mm-mmap-dont-use-__vma_adjust-in-shift_arg_pages.patch
mm-mmap-introduce-dup_vma_anon-helper.patch
mm-mmap-convert-do_brk_flags-to-use-vma_prepare-and-vma_complete.patch
mm-mmap-remove-__vma_adjust.patch
vma_merge-set-vma-iterator-to-correct-position.patch
