Re: [PATCH 4/7 v2] tracing: Have trace events system open call tracing_open_generic_tr()
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2019-10-12 02:09:46
Also in:
linux-api, lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
On Fri, 11 Oct 2019 20:57:51 -0400 Steven Rostedt [off-list ref] wrote:
quoted hunk ↗ jump to hunk
--- 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)" <rostedt@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) <rostedt@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