[PATCH 1/3] trace_stat: Fix missing entry in stat file

From: Li Zefan
Date: Mon Aug 17 2009 - 04:56:01 EST


One entry is missing in the output of a stat file.

The cause is, when stat_seq_start() is called the 2nd time, we should
start from the (pos-1)th elem in the rbtree but not pos, because
pos == 0 is the header.

Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
---
kernel/trace/trace_stat.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 07c60b0..a4bb239 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -203,17 +203,21 @@ static void *stat_seq_start(struct seq_file *s, loff_t *pos)
{
struct stat_session *session = s->private;
struct rb_node *node;
+ int n = *pos;
int i;

/* Prevent from tracer switch or rbtree modification */
mutex_lock(&session->stat_mutex);

/* If we are in the beginning of the file, print the headers */
- if (!*pos && session->ts->stat_headers)
- return SEQ_START_TOKEN;
+ if (session->ts->stat_headers) {
+ if (n == 0)
+ return SEQ_START_TOKEN;
+ n--;
+ }

node = rb_first(&session->stat_root);
- for (i = 0; node && i < *pos; i++)
+ for (i = 0; node && i < n; i++)
node = rb_next(node);

return node;
--
1.6.3
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