diff options
author | Oleg Nesterov <oleg@redhat.com> | 2014-10-10 02:25:28 +0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-10 06:25:48 +0400 |
commit | 59b4bf12d4776c0e4f3fd5c02d942f3a0596da97 (patch) | |
tree | a54941f4adce9529e88099ad4a17e7e2edef90a8 /fs/proc | |
parent | 29a40ace841cba9b661711f042d1821cdc4ad47c (diff) | |
download | linux-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.c | 35 |
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); } |