[PATCH 1/7] ftrace: Change filter/notrace set functions to return exit code

From: Jiri Olsa
Date: Wed Jan 18 2012 - 13:44:50 EST


Currently the ftrace_set_filter and ftrace_set_notrace functions
do not return any return code. So there's no way for ftrace_ops
user to tell wether the filter was correctly applied.

The set_ftrace_filter interface returns error in case the filter
did not match:

# echo krava > set_ftrace_filter
bash: echo: write error: Invalid argument

Changing both ftrace_set_filter and ftrace_set_notrace functions
to return zero if the filter was applied correctly or -E* values
in case of error.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
include/linux/ftrace.h | 4 ++--
kernel/trace/ftrace.c | 15 +++++++++------
2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 028e26f..f33fb3b 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -178,9 +178,9 @@ struct dyn_ftrace {
};

int ftrace_force_update(void);
-void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
+int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset);
-void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
+int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset);
void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 683d559..e2e0597 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3146,8 +3146,10 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
mutex_lock(&ftrace_regex_lock);
if (reset)
ftrace_filter_reset(hash);
- if (buf)
- ftrace_match_records(hash, buf, len);
+ if (buf && !ftrace_match_records(hash, buf, len)) {
+ ret = -EINVAL;
+ goto out_regex_unlock;
+ }

mutex_lock(&ftrace_lock);
ret = ftrace_hash_move(ops, enable, orig_hash, hash);
@@ -3157,6 +3159,7 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,

mutex_unlock(&ftrace_lock);

+ out_regex_unlock:
mutex_unlock(&ftrace_regex_lock);

free_ftrace_hash(hash);
@@ -3173,10 +3176,10 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
* Filters denote which functions should be enabled when tracing is enabled.
* If @buf is NULL and reset is set, all functions will be enabled for tracing.
*/
-void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
+int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset)
{
- ftrace_set_regex(ops, buf, len, reset, 1);
+ return ftrace_set_regex(ops, buf, len, reset, 1);
}
EXPORT_SYMBOL_GPL(ftrace_set_filter);

@@ -3191,10 +3194,10 @@ EXPORT_SYMBOL_GPL(ftrace_set_filter);
* is enabled. If @buf is NULL and reset is set, all functions will be enabled
* for tracing.
*/
-void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
+int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset)
{
- ftrace_set_regex(ops, buf, len, reset, 0);
+ return ftrace_set_regex(ops, buf, len, reset, 0);
}
EXPORT_SYMBOL_GPL(ftrace_set_notrace);
/**
--
1.7.1

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