lkml.org 
[lkml]   [2013]   [Oct]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3/4] ftrace: Narrow down the protected area of graph_lock
Date
From: Namhyung Kim <namhyung.kim@lge.com>

It seems that it doesn't need to hold graph_lock during preparation of
the trace_parser. At least it makes the code a bit simpler IMHO.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
kernel/trace/ftrace.c | 22 +++++++++-------------
1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0ff3449b4272..26a229ab0c19 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3973,37 +3973,33 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_parser parser;
- ssize_t read, ret;
+ ssize_t read, ret = 0;
struct ftrace_graph_data *fgd = file->private_data;

if (!cnt)
return 0;

- mutex_lock(&graph_lock);
-
- if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
- ret = -ENOMEM;
- goto out_unlock;
- }
+ if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
+ return -ENOMEM;

read = trace_get_user(&parser, ubuf, cnt, ppos);

if (read >= 0 && trace_parser_loaded((&parser))) {
parser.buffer[parser.idx] = 0;

+ mutex_lock(&graph_lock);
+
/* we allow only one expression at a time */
ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
parser.buffer);
- if (ret)
- goto out_free;
+
+ mutex_unlock(&graph_lock);
}

- ret = read;
+ if (!ret)
+ ret = read;

-out_free:
trace_parser_put(&parser);
-out_unlock:
- mutex_unlock(&graph_lock);

return ret;
}
--
1.7.11.7


\
 
 \ /
  Last update: 2013-10-14 11:21    [W:0.033 / U:6.664 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site