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Subject[PATCH v2 6/7] fs/proc/task_mmu.c: cleanup the "tail_vma" horror in m_next()
1. Kill the first "vma != NULL" check. Firstly this is not possible,
m_next() won't be called if ->start() or the previous ->next()
returns NULL.

And if it was possible the 2nd "vma != tail_vma" check is buggy,
we should not wrongly return ->tail_vma.

2. Make this function readable. The logic is very simple, we should
return check "vma != tail" once and return "vm_next || tail_vma".

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
fs/proc/task_mmu.c | 8 +++-----
1 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index f1254b4..c4c8825 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -209,15 +209,13 @@ out:
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
struct proc_maps_private *priv = m->private;
- struct vm_area_struct *vma = v;
struct vm_area_struct *tail_vma = priv->tail_vma;
- struct vm_area_struct *next;
+ struct vm_area_struct *vma = v, *next = NULL;

(*pos)++;
- if (vma && (vma != tail_vma) && vma->vm_next)
- return vma->vm_next;
+ if (vma != tail_vma)
+ next = vma->vm_next ?: tail_vma;

- next = (vma != tail_vma)? tail_vma: NULL;
if (!next)
vma_stop(priv);
return next;
--
1.5.5.1


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