The patch titled
Subject: fs/proc/task_mmu.c: simplify m_start() to make it readable
has been added to the -mm tree. Its filename is
fs-proc-task_mmuc-simplify-m_start-to-make-it-readable.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fs-proc-task_mmuc-simplify-m_start-to-make-it-readable.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fs-proc-task_mmuc-simplify-m_start-to-make-it-readable.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: fs/proc/task_mmu.c: simplify m_start() to make it readable
Now that m->version is gone we can cleanup m_start(). In particular,
- Remove the "unsigned long" typecast, m->index can't be negative
or exceed ->map_count. But lets use "unsigned int pos" to make
it clear that "pos < map_count" is safe.
- Remove the unnecessary "vma != NULL" check in the main loop. It
can't be NULL unless we have a vm bug.
- This also means that "pos < map_count" case can simply return the
valid vma and avoid "goto" and subsequent checks.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: 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, 10 insertions(+), 24 deletions(-)
diff -puN fs/proc/task_mmu.c~fs-proc-task_mmuc-simplify-m_start-to-make-it-readable fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~fs-proc-task_mmuc-simplify-m_start-to-make-it-readable
+++ a/fs/proc/task_mmu.c
@@ -137,12 +137,12 @@ static void vma_stop(struct proc_maps_pr
mmput(mm);
}
-static void *m_start(struct seq_file *m, loff_t *pos)
+static void *m_start(struct seq_file *m, loff_t *ppos)
{
struct proc_maps_private *priv = m->private;
struct mm_struct *mm;
- struct vm_area_struct *vma, *tail_vma = NULL;
- loff_t l = *pos;
+ struct vm_area_struct *vma;
+ unsigned int pos = *ppos;
priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
if (!priv->task)
@@ -151,33 +151,19 @@ static void *m_start(struct seq_file *m,
mm = priv->mm;
if (!mm || !atomic_inc_not_zero(&mm->mm_users))
return NULL;
- down_read(&mm->mmap_sem);
- tail_vma = get_gate_vma(mm);
- priv->tail_vma = tail_vma;
+ down_read(&mm->mmap_sem);
hold_task_mempolicy(priv);
+ priv->tail_vma = get_gate_vma(mm);
- /*
- * Check the vma index is within the range and do
- * sequential scan until m_index.
- */
- vma = NULL;
- if ((unsigned long)l < mm->map_count) {
- vma = mm->mmap;
- while (l-- && vma)
+ if (pos < mm->map_count) {
+ for (vma = mm->mmap; pos; pos--)
vma = vma->vm_next;
- goto out;
- }
-
- if (l != mm->map_count)
- tail_vma = NULL; /* After gate vma */
-
-out:
- if (vma)
return vma;
+ }
- if (tail_vma)
- return tail_vma;
+ if (pos == mm->map_count && priv->tail_vma)
+ return priv->tail_vma;
vma_stop(priv);
return NULL;
_
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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