The patch titled
Subject: fs/proc/task_mmu.c: simplify the vma_stop() logic
has been added to the -mm tree. Its filename is
fs-proc-task_mmuc-simplify-the-vma_stop-logic.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fs-proc-task_mmuc-simplify-the-vma_stop-logic.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fs-proc-task_mmuc-simplify-the-vma_stop-logic.patch
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: 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.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)
diff -puN fs/proc/task_mmu.c~fs-proc-task_mmuc-simplify-the-vma_stop-logic fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~fs-proc-task_mmuc-simplify-the-vma_stop-logic
+++ a/fs/proc/task_mmu.c
@@ -129,14 +129,12 @@ static void release_task_mempolicy(struc
}
#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 +197,13 @@ 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 +211,24 @@ static void *m_next(struct seq_file *m,
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);
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
earlyprintk-re-enable-earlyprintk-calling-early_param.patch
fs-proc-task_mmuc-dont-use-task-mm-in-m_start-and-show_map.patch
fs-proc-task_mmuc-unify-simplify-do_maps_open-and-numa_maps_open.patch
proc-introduce-proc_mem_open.patch
fs-proc-task_mmuc-shift-mm_access-from-m_start-to-proc_maps_open.patch
fs-proc-task_mmuc-simplify-the-vma_stop-logic.patch
fs-proc-task_mmuc-cleanup-the-tail_vma-horror-in-m_next.patch
fs-proc-task_mmuc-shift-priv-task-=-null-from-m_start-to-m_stop.patch
fs-proc-task_mmuc-kill-the-suboptimal-and-confusing-m-version-logic.patch
fs-proc-task_mmuc-simplify-m_start-to-make-it-readable.patch
fs-proc-task_mmuc-introduce-m_next_vma-helper.patch
fs-proc-task_mmuc-reintroduce-m-version-logic.patch
fs-proc-task_mmuc-update-m-version-in-the-main-loop-in-m_start.patch
fs-proc-task_nommuc-change-maps_open-to-use-__seq_open_private.patch
fs-proc-task_nommuc-shift-mm_access-from-m_start-to-proc_maps_open.patch
fs-proc-task_nommuc-dont-use-priv-task-mm.patch
linux-next.patch
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