[for-next][PATCH 09/10] tracing: Add generic tracing_lseek() function

Steven Rostedt
2013-12-23T21:39:26Z

[-- Attachment #1: 0009-tracing-Add-generic-tracing_lseek-function.patch --]
[-- Type: text/plain, Size: 6484 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Trace event triggers added a lseek that uses the ftrace_filter_lseek()
function. Unfortunately, when function tracing is not configured in
that function is not defined and the kernel fails to build.

This is the second time that function was added to a file ops and
it broke the build due to requiring special config dependencies.

Make a generic tracing_lseek() that all the tracing utilities may
use.

Also, modify the old ftrace_filter_lseek() to return 0 instead of
1 on WRONLY. Not sure why it was a 1 as that does not make sense.

This also changes the old tracing_seek() to modify the file pos
pointer on WRONLY as well.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/ftrace.h | 2 --
kernel/trace/ftrace.c | 25 ++++++-------------------
kernel/trace/trace.c | 14 +++++++++-----
kernel/trace/trace.h | 2 ++
kernel/trace/trace_events_trigger.c | 2 +-
kernel/trace/trace_stack.c | 2 +-
6 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 31ea4b4..f4233b1 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -570,8 +570,6 @@ static inline int
ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
#endif /* CONFIG_DYNAMIC_FTRACE */

-loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence);
-
/* totally disable ftrace - can not re-enable after this */
void ftrace_kill(void);

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0e9f9ea..531ffa6 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1082,19 +1082,6 @@ static __init void ftrace_profile_debugfs(struct dentry *d_tracer)

static struct pid * const ftrace_swapper_pid = &init_struct_pid;

-loff_t
-ftrace_filter_lseek(struct file *file, loff_t offset, int whence)
-{
- loff_t ret;
-
- if (file->f_mode & FMODE_READ)
- ret = seq_lseek(file, offset, whence);
- else
- file->f_pos = ret = 1;
-
- return ret;
-}
-
#ifdef CONFIG_DYNAMIC_FTRACE

#ifndef CONFIG_FTRACE_MCOUNT_RECORD
@@ -2739,7 +2726,7 @@ static void ftrace_filter_reset(struct ftrace_hash *hash)
* routine, you can use ftrace_filter_write() for the write
* routine if @flag has FTRACE_ITER_FILTER set, or
* ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
- * ftrace_filter_lseek() should be used as the lseek routine, and
+ * tracing_lseek() should be used as the lseek routine, and
* release must call ftrace_regex_release().
*/
int
@@ -3767,7 +3754,7 @@ static const struct file_operations ftrace_filter_fops = {
.open = ftrace_filter_open,
.read = seq_read,
.write = ftrace_filter_write,
- .llseek = ftrace_filter_lseek,
+ .llseek = tracing_lseek,
.release = ftrace_regex_release,
};

@@ -3775,7 +3762,7 @@ static const struct file_operations ftrace_notrace_fops = {
.open = ftrace_notrace_open,
.read = seq_read,
.write = ftrace_notrace_write,
- .llseek = ftrace_filter_lseek,
+ .llseek = tracing_lseek,
.release = ftrace_regex_release,
};

@@ -4038,7 +4025,7 @@ static const struct file_operations ftrace_graph_fops = {
.open = ftrace_graph_open,
.read = seq_read,
.write = ftrace_graph_write,
- .llseek = ftrace_filter_lseek,
+ .llseek = tracing_lseek,
.release = ftrace_graph_release,
};

@@ -4046,7 +4033,7 @@ static const struct file_operations ftrace_graph_notrace_fops = {
.open = ftrace_graph_notrace_open,
.read = seq_read,
.write = ftrace_graph_write,
- .llseek = ftrace_filter_lseek,
+ .llseek = tracing_lseek,
.release = ftrace_graph_release,
};
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
@@ -4719,7 +4706,7 @@ static const struct file_operations ftrace_pid_fops = {
.open = ftrace_pid_open,
.write = ftrace_pid_write,
.read = seq_read,
- .llseek = ftrace_filter_lseek,
+ .llseek = tracing_lseek,
.release = ftrace_pid_release,
};

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 59bf5b5..e32a2f4 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3183,19 +3183,23 @@ tracing_write_stub(struct file *filp, const char __user *ubuf,
return count;
}

-static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
+loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
{
+ int ret;
+
if (file->f_mode & FMODE_READ)
- return seq_lseek(file, offset, origin);
+ ret = seq_lseek(file, offset, whence);
else
- return 0;
+ file->f_pos = ret = 0;
+
+ return ret;
}

static const struct file_operations tracing_fops = {
.open = tracing_open,
.read = seq_read,
.write = tracing_write_stub,
- .llseek = tracing_seek,
+ .llseek = tracing_lseek,
.release = tracing_release,
};

@@ -4940,7 +4944,7 @@ static const struct file_operations snapshot_fops = {
.open = tracing_snapshot_open,
.read = seq_read,
.write = tracing_snapshot_write,
- .llseek = tracing_seek,
+ .llseek = tracing_lseek,
.release = tracing_snapshot_release,
};

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 433bfc5..0380cab 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -588,6 +588,8 @@ void tracing_start_sched_switch_record(void);
int register_tracer(struct tracer *type);
int is_tracing_stopped(void);

+loff_t tracing_lseek(struct file *file, loff_t offset, int whence);
+
extern cpumask_var_t __read_mostly tracing_buffer_mask;

#define for_each_tracing_cpu(cpu) \
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index f5b3f78..12ac8a5 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -281,7 +281,7 @@ const struct file_operations event_trigger_fops = {
.open = event_trigger_open,
.read = seq_read,
.write = event_trigger_write,
- .llseek = ftrace_filter_lseek,
+ .llseek = tracing_lseek,
.release = event_trigger_release,
};

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index b20428c..e6be585 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -382,7 +382,7 @@ static const struct file_operations stack_trace_filter_fops = {
.open = stack_trace_filter_open,
.read = seq_read,
.write = ftrace_filter_write,
- .llseek = ftrace_filter_lseek,
+ .llseek = tracing_lseek,
.release = ftrace_regex_release,
};

--
1.8.4.3