The patch titled
Subject: mm/mmap: introduce init_vma_prep() and init_multi_vma_prep()
has been added to the -mm mm-unstable branch. Its filename is
mm-mmap-introduce-init_vma_prep-and-init_multi_vma_prep.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mmap-introduce-init_vma_prep-and-init_multi_vma_prep.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: mm/mmap: introduce init_vma_prep() and init_multi_vma_prep()
Date: Fri, 20 Jan 2023 11:26:43 -0500
Add init_vma_prep() and init_multi_vma_prep() to set up the struct
vma_prepare. This is to abstract the locking when adjusting the VMAs.
Also change __vma_adjust() variable remove_next int in favour of a pointer
to the VMA to remove. Rename next_next to remove2 since this better
reflects its use.
Link: https://lkml.kernel.org/r/20230120162650.984577-43-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/mmap.c~mm-mmap-introduce-init_vma_prep-and-init_multi_vma_prep
+++ a/mm/mmap.c
@@ -461,6 +461,45 @@ static int vma_link(struct mm_struct *mm
}
/*
+ * init_multi_vma_prep() - Initializer for struct vma_prepare
+ * @vp: The vma_prepare struct
+ * @vma: The vma that will be altered once locked
+ * @next: The next vma if it is to be adjusted
+ * @remove: The first vma to be removed
+ * @remove2: The second vma to be removed
+ */
+static inline void init_multi_vma_prep(struct vma_prepare *vp,
+ struct vm_area_struct *vma, struct vm_area_struct *next,
+ struct vm_area_struct *remove, struct vm_area_struct *remove2)
+{
+ memset(vp, 0, sizeof(struct vma_prepare));
+ vp->vma = vma;
+ vp->anon_vma = vma->anon_vma;
+ vp->remove = remove;
+ vp->remove2 = remove2;
+ vp->adj_next = next;
+ if (!vp->anon_vma && next)
+ vp->anon_vma = next->anon_vma;
+
+ vp->file = vma->vm_file;
+ if (vp->file)
+ vp->mapping = vma->vm_file->f_mapping;
+
+}
+
+/*
+ * init_vma_prep() - Initializer wrapper for vma_prepare struct
+ * @vp: The vma_prepare struct
+ * @vma: The vma that will be altered once locked
+ */
+static inline void init_vma_prep(struct vma_prepare *vp,
+ struct vm_area_struct *vma)
+{
+ init_multi_vma_prep(vp, vma, NULL, NULL, NULL);
+}
+
+
+/*
* vma_prepare() - Helper function for handling locking VMAs prior to altering
* @vp: The initialized vma_prepare struct
*/
@@ -569,7 +608,7 @@ again:
/*
* In mprotect's case 6 (see comments on vma_merge),
- * we must remove next_next too.
+ * we must remove the one after next as well.
*/
if (vp->remove2) {
vp->remove = vp->remove2;
@@ -602,17 +641,14 @@ inline int vma_expand(struct vma_iterato
unsigned long start, unsigned long end, pgoff_t pgoff,
struct vm_area_struct *next)
{
+ bool remove_next = false;
struct vma_prepare vp;
- memset(&vp, 0, sizeof(vp));
- vp.vma = vma;
- vp.anon_vma = vma->anon_vma;
if (next && (vma != next) && (end == next->vm_end)) {
- vp.remove = next;
+ remove_next = true;
if (next->anon_vma && !vma->anon_vma) {
int error;
- vp.anon_vma = next->anon_vma;
vma->anon_vma = next->anon_vma;
error = anon_vma_clone(vma, next);
if (error)
@@ -620,6 +656,7 @@ inline int vma_expand(struct vma_iterato
}
}
+ init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL);
/* Not merging but overwriting any part of next is not handled. */
VM_WARN_ON(next && !vp.remove &&
next != vma && end > next->vm_start);
@@ -630,11 +667,6 @@ inline int vma_expand(struct vma_iterato
goto nomem;
vma_adjust_trans_huge(vma, start, end, 0);
-
- vp.file = vma->vm_file;
- if (vp.file)
- vp.mapping = vp.file->f_mapping;
-
/* VMA iterator points to previous, so set to start if necessary */
if (vma_iter_addr(vmi) != start)
vma_iter_set(vmi, start);
@@ -665,14 +697,13 @@ int __vma_adjust(struct vma_iterator *vm
struct vm_area_struct *insert, struct vm_area_struct *expand)
{
struct mm_struct *mm = vma->vm_mm;
- struct vm_area_struct *next_next = NULL; /* uninit var warning */
+ struct vm_area_struct *remove2 = NULL;
+ struct vm_area_struct *remove = NULL;
struct vm_area_struct *next = find_vma(mm, vma->vm_end);
struct vm_area_struct *orig_vma = vma;
- struct anon_vma *anon_vma = NULL;
struct file *file = vma->vm_file;
bool vma_changed = false;
long adjust_next = 0;
- int remove_next = 0;
struct vm_area_struct *exporter = NULL, *importer = NULL;
struct vma_prepare vma_prep;
@@ -691,25 +722,24 @@ int __vma_adjust(struct vma_iterator *vm
*/
VM_WARN_ON(end != next->vm_end);
/*
- * remove_next == 3 means we're
- * removing "vma" and that to do so we
+ * we're removing "vma" and that to do so we
* swapped "vma" and "next".
*/
- remove_next = 3;
VM_WARN_ON(file != next->vm_file);
swap(vma, next);
+ remove = next;
} else {
VM_WARN_ON(expand != vma);
/*
- * case 1, 6, 7, remove_next == 2 is case 6,
- * remove_next == 1 is case 1 or 7.
+ * case 1, 6, 7, remove next.
+ * case 6 also removes the one beyond next
*/
- remove_next = 1 + (end > next->vm_end);
- if (remove_next == 2)
- next_next = find_vma(mm, next->vm_end);
+ remove = next;
+ if (end > next->vm_end)
+ remove2 = find_vma(mm, next->vm_end);
- VM_WARN_ON(remove_next == 2 &&
- end != next_next->vm_end);
+ VM_WARN_ON(remove2 != NULL &&
+ end != remove2->vm_end);
}
exporter = next;
@@ -719,8 +749,8 @@ int __vma_adjust(struct vma_iterator *vm
* If next doesn't have anon_vma, import from vma after
* next, if the vma overlaps with it.
*/
- if (remove_next == 2 && !next->anon_vma)
- exporter = next_next;
+ if (remove2 != NULL && !next->anon_vma)
+ exporter = remove2;
} else if (end > next->vm_start) {
/*
@@ -761,30 +791,14 @@ int __vma_adjust(struct vma_iterator *vm
if (vma_iter_prealloc(vmi))
return -ENOMEM;
- anon_vma = vma->anon_vma;
- if (!anon_vma && adjust_next)
- anon_vma = next->anon_vma;
-
- if (anon_vma)
- VM_WARN_ON(adjust_next && next->anon_vma &&
- anon_vma != next->anon_vma);
-
vma_adjust_trans_huge(orig_vma, start, end, adjust_next);
- memset(&vma_prep, 0, sizeof(vma_prep));
- vma_prep.vma = vma;
- vma_prep.anon_vma = anon_vma;
- vma_prep.file = file;
- if (adjust_next)
- vma_prep.adj_next = next;
- if (file)
- vma_prep.mapping = file->f_mapping;
- vma_prep.insert = insert;
- if (remove_next) {
- vma_prep.remove = next;
- vma_prep.remove2 = next_next;
- }
+ init_multi_vma_prep(&vma_prep, vma, adjust_next ? next : NULL, remove,
+ remove2);
+ 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) {
_
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
