On Fri, 11 Oct 2019 20:57:51 -0400
Steven Rostedt <rost...@goodmis.org> wrote:
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -1391,9 +1391,6 @@ static int subsystem_open(struct inode *inode, struct
> file *filp)
> struct trace_array *tr;
> int ret;
>
> - if (tracing_is_disabled())
> - return -ENODEV;
> -
> /* Make sure the system still exists */
> mutex_lock(&event_mutex);
> mutex_lock(&trace_types_lock);
> @@ -1420,16 +1417,9 @@ static int subsystem_open(struct inode *inode, struct
> file *filp)
> WARN_ON(!dir);
>
> /* Still need to increment the ref count of the system */
> - if (trace_array_get(tr) < 0) {
> - put_system(dir);
> - return -ENODEV;
> - }
> -
> - ret = tracing_open_generic(inode, filp);
> - if (ret < 0) {
> - trace_array_put(tr);
> + ret = tracing_open_generic_tr(inode, filp);
> + if (ret < 0)
> put_system(dir);
> - }
>
> return ret;
> }
I got a bit too aggressive on this patch. The subsystem_open() gets the
tr from a search, not from the inode. Thus it can't use the
tracing_open_generic_tr() call. It needs to do the trace_array_get()
directly.
V2 of this patch:
-- Steve
>From b69083301044f587afefd5a4ac754a8c43ba0f0d Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rost...@goodmis.org>
Date: Fri, 11 Oct 2019 19:12:21 -0400
Subject: [PATCH] tracing: Have trace events system open call
tracing_open_generic_tr()
Instead of having the trace events system open calls open code the taking of
the trace_array descriptor (with trace_array_get()) and then calling
trace_open_generic(), have it use the tracing_open_generic_tr() that does
the combination of the two. This requires making tracing_open_generic_tr()
global.
Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org>
---
kernel/trace/trace.c | 2 +-
kernel/trace/trace.h | 1 +
kernel/trace/trace_events.c | 17 +++--------------
3 files changed, 5 insertions(+), 15 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index fa7d813b04c6..94f1b9124939 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4156,7 +4156,7 @@ bool tracing_is_disabled(void)
* Open and update trace_array ref count.
* Must have the current trace_array passed to it.
*/
-static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
+int tracing_open_generic_tr(struct inode *inode, struct file *filp)
{
struct trace_array *tr = inode->i_private;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f801d154ff6a..854dbf4050f8 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -681,6 +681,7 @@ void tracing_reset_online_cpus(struct trace_buffer *buf);
void tracing_reset_current(int cpu);
void tracing_reset_all_online_cpus(void);
int tracing_open_generic(struct inode *inode, struct file *filp);
+int tracing_open_generic_tr(struct inode *inode, struct file *filp);
bool tracing_is_disabled(void);
bool tracer_tracing_is_on(struct trace_array *tr);
void tracer_tracing_on(struct trace_array *tr);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index b89cdfe20bc1..9613a757c902 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1440,28 +1440,17 @@ static int system_tr_open(struct inode *inode, struct
file *filp)
struct trace_array *tr = inode->i_private;
int ret;
- if (tracing_is_disabled())
- return -ENODEV;
-
- if (trace_array_get(tr) < 0)
- return -ENODEV;
-
/* Make a temporary dir that has no system but points to tr */
dir = kzalloc(sizeof(*dir), GFP_KERNEL);
- if (!dir) {
- trace_array_put(tr);
+ if (!dir)
return -ENOMEM;
- }
-
- dir->tr = tr;
- ret = tracing_open_generic(inode, filp);
+ ret = tracing_open_generic_tr(inode, filp);
if (ret < 0) {
- trace_array_put(tr);
kfree(dir);
return ret;
}
-
+ dir->tr = tr;
filp->private_data = dir;
return 0;
--
2.20.1
