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authorOleg Nesterov <oleg@redhat.com>2014-10-10 02:25:28 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-10 06:25:48 +0400
commit59b4bf12d4776c0e4f3fd5c02d942f3a0596da97 (patch)
treea54941f4adce9529e88099ad4a17e7e2edef90a8 /fs/proc
parent29a40ace841cba9b661711f042d1821cdc4ad47c (diff)
downloadlinux-59b4bf12d4776c0e4f3fd5c02d942f3a0596da97.tar.xz
fs/proc/task_mmu.c: simplify the vma_stop() logic
m_start() drops ->mmap_sem and does mmput() if it retuns vsyscall vma. This is because in this case m_stop()->vma_stop() obviously can't use gate_vma->vm_mm. Now that we have proc_maps_private->mm we can simplify this logic: - Change m_start() to return with ->mmap_sem held unless it returns IS_ERR_OR_NULL(). - Change vma_stop() to use priv->mm and avoid the ugly vma checks, this makes "vm_area_struct *vma" unnecessary. - This also allows m_start() to use vm_stop(). - Cleanup m_next() to follow the new locking rule. Note: m_stop() looks very ugly, and this temporary uglifies it even more. Fixed by the next change. [akpm@linux-foundation.org: coding-style fixes] 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>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/task_mmu.c35
1 files changed, 19 insertions, 16 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index a1454dac7e0a..fdbed8370db6 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -129,14 +129,13 @@ static void release_task_mempolicy(struct proc_maps_private *priv)
}
#endif
-static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma)
+static void vma_stop(struct proc_maps_private *priv)
{
- if (vma && vma != priv->tail_vma) {
- struct mm_struct *mm = vma->vm_mm;
- release_task_mempolicy(priv);
- up_read(&mm->mmap_sem);
- mmput(mm);
- }
+ struct mm_struct *mm = priv->mm;
+
+ release_task_mempolicy(priv);
+ up_read(&mm->mmap_sem);
+ mmput(mm);
}
static void *m_start(struct seq_file *m, loff_t *pos)
@@ -199,12 +198,13 @@ out:
if (vma)
return vma;
- release_task_mempolicy(priv);
/* End of vmas has been reached */
m->version = (tail_vma != NULL)? 0: -1UL;
- up_read(&mm->mmap_sem);
- mmput(mm);
- return tail_vma;
+ if (tail_vma)
+ return tail_vma;
+
+ vma_stop(priv);
+ return NULL;
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
@@ -212,21 +212,24 @@ 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;
(*pos)++;
if (vma && (vma != tail_vma) && vma->vm_next)
return vma->vm_next;
- vma_stop(priv, vma);
- return (vma != tail_vma)? tail_vma: NULL;
+
+ next = (vma != tail_vma) ? tail_vma : NULL;
+ if (!next)
+ vma_stop(priv);
+ return next;
}
static void m_stop(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
- struct vm_area_struct *vma = v;
- if (!IS_ERR(vma))
- vma_stop(priv, vma);
+ if (!IS_ERR_OR_NULL(v))
+ vma_stop(priv);
if (priv->task)
put_task_struct(priv->task);
}