[PATCH v7 18/70] proc: Remove VMA rbtree use from nommu

Liam Howlett
2022-04-04T14:36:35Z

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

These users of the rbtree should probably have been walks of the
linked list, but convert them to use walks of the maple tree.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
fs/proc/task_nommu.c | 45 +++++++++++++++++++++-----------------------
1 file changed, 21 insertions(+), 24 deletions(-)

diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index a6d21fc0033c..2fd06f52b6a4 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -20,15 +20,13 @@
*/
void task_mem(struct seq_file *m, struct mm_struct *mm)
{
+ VMA_ITERATOR(vmi, mm, 0);
struct vm_area_struct *vma;
struct vm_region *region;
- struct rb_node *p;
unsigned long bytes = 0, sbytes = 0, slack = 0, size;
-
- mmap_read_lock(mm);
- for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
- vma = rb_entry(p, struct vm_area_struct, vm_rb);

+ mmap_read_lock(mm);
+ for_each_vma(vmi, vma) {
bytes += kobjsize(vma);

region = vma->vm_region;
@@ -82,15 +80,13 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)

unsigned long task_vsize(struct mm_struct *mm)
{
+ VMA_ITERATOR(vmi, mm, 0);
struct vm_area_struct *vma;
- struct rb_node *p;
unsigned long vsize = 0;

mmap_read_lock(mm);
- for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
- vma = rb_entry(p, struct vm_area_struct, vm_rb);
+ for_each_vma(vmi, vma)
vsize += vma->vm_end - vma->vm_start;
- }
mmap_read_unlock(mm);
return vsize;
}
@@ -99,14 +95,13 @@ unsigned long task_statm(struct mm_struct *mm,
unsigned long *shared, unsigned long *text,
unsigned long *data, unsigned long *resident)
{
+ VMA_ITERATOR(vmi, mm, 0);
struct vm_area_struct *vma;
struct vm_region *region;
- struct rb_node *p;
unsigned long size = kobjsize(mm);

mmap_read_lock(mm);
- for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
- vma = rb_entry(p, struct vm_area_struct, vm_rb);
+ for_each_vma(vmi, vma) {
size += kobjsize(vma);
region = vma->vm_region;
if (region) {
@@ -190,17 +185,19 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
*/
static int show_map(struct seq_file *m, void *_p)
{
- struct rb_node *p = _p;
-
- return nommu_vma_show(m, rb_entry(p, struct vm_area_struct, vm_rb));
+ return nommu_vma_show(m, _p);
}

static void *m_start(struct seq_file *m, loff_t *pos)
{
struct proc_maps_private *priv = m->private;
struct mm_struct *mm;
- struct rb_node *p;
- loff_t n = *pos;
+ struct vm_area_struct *vma;
+ unsigned long addr = *pos;
+
+ /* See m_next(). Zero at the start or after lseek. */
+ if (addr == -1UL)
+ return NULL;

/* pin the task and mm whilst we play with them */
priv->task = get_proc_task(priv->inode);
@@ -216,10 +213,10 @@ static void *m_start(struct seq_file *m, loff_t *pos)
return ERR_PTR(-EINTR);
}

- /* start from the Nth VMA */
- for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
- if (n-- == 0)
- return p;
+ /* start the next element from addr */
+ vma = find_vma(mm, addr);
+ if (vma)
+ return vma;

mmap_read_unlock(mm);
mmput(mm);
@@ -242,10 +239,10 @@ static void m_stop(struct seq_file *m, void *_vml)

static void *m_next(struct seq_file *m, void *_p, loff_t *pos)
{
- struct rb_node *p = _p;
+ struct vm_area_struct *vma = _p;

- (*pos)++;
- return p ? rb_next(p) : NULL;
+ *pos = vma->vm_end;
+ return find_vma(vma->vm_mm, vma->vm_end);
}

static const struct seq_operations proc_pid_maps_ops = {
--
2.34.1