Commit 23d54837 authored Oct 09, 2014 by Oleg Nesterov Committed by Linus Torvalds Oct 09, 2014

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>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 59b4bf12

fs/proc/task_mmu.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -210,15 +210,13 @@ 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;

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