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Date: Wed, 31 Jul 2013 19:31:32 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Steven Rostedt <rostedt@...dmis.org>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...hat.com>,
"zhangwei(Jovi)" <jovi.zhangwei@...wei.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] tracing: Kill trace_create_file_ops() and friends
trace_create_file_ops() allocates the copy of id/filter/format/enable
file_operations to set "f_op->owner = mod" for fops_get().
However after the recent changes there is no reason to prevent rmmod
even if one of these files is opened. A file operation can do nothing
but fail after remove_event_file_dir() clears ->i_private for every
file removed by trace_module_remove_events().
Kill "struct ftrace_module_file_ops" and fix the compilation errors.
Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
kernel/trace/trace_events.c | 153 +++----------------------------------------
1 files changed, 9 insertions(+), 144 deletions(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 3450496..5fcd18b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1679,8 +1679,7 @@ __trace_early_add_new_event(struct ftrace_event_call *call,
}
struct ftrace_module_file_ops;
-static void __add_event_to_tracers(struct ftrace_event_call *call,
- struct ftrace_module_file_ops *file_ops);
+static void __add_event_to_tracers(struct ftrace_event_call *call);
/* Add an additional event_call dynamically */
int trace_add_event_call(struct ftrace_event_call *call)
@@ -1691,7 +1690,7 @@ int trace_add_event_call(struct ftrace_event_call *call)
ret = __register_event(call, NULL);
if (ret >= 0)
- __add_event_to_tracers(call, NULL);
+ __add_event_to_tracers(call);
mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
@@ -1759,100 +1758,21 @@ int trace_remove_event_call(struct ftrace_event_call *call)
#ifdef CONFIG_MODULES
-static LIST_HEAD(ftrace_module_file_list);
-
-/*
- * Modules must own their file_operations to keep up with
- * reference counting.
- */
-struct ftrace_module_file_ops {
- struct list_head list;
- struct module *mod;
- struct file_operations id;
- struct file_operations enable;
- struct file_operations format;
- struct file_operations filter;
-};
-
-static struct ftrace_module_file_ops *
-find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
-{
- /*
- * As event_calls are added in groups by module,
- * when we find one file_ops, we don't need to search for
- * each call in that module, as the rest should be the
- * same. Only search for a new one if the last one did
- * not match.
- */
- if (file_ops && mod == file_ops->mod)
- return file_ops;
-
- list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
- if (file_ops->mod == mod)
- return file_ops;
- }
- return NULL;
-}
-
-static struct ftrace_module_file_ops *
-trace_create_file_ops(struct module *mod)
-{
- struct ftrace_module_file_ops *file_ops;
-
- /*
- * This is a bit of a PITA. To allow for correct reference
- * counting, modules must "own" their file_operations.
- * To do this, we allocate the file operations that will be
- * used in the event directory.
- */
-
- file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
- if (!file_ops)
- return NULL;
-
- file_ops->mod = mod;
-
- file_ops->id = ftrace_event_id_fops;
- file_ops->id.owner = mod;
-
- file_ops->enable = ftrace_enable_fops;
- file_ops->enable.owner = mod;
-
- file_ops->filter = ftrace_event_filter_fops;
- file_ops->filter.owner = mod;
-
- file_ops->format = ftrace_event_format_fops;
- file_ops->format.owner = mod;
-
- list_add(&file_ops->list, &ftrace_module_file_list);
-
- return file_ops;
-}
-
static void trace_module_add_events(struct module *mod)
{
- struct ftrace_module_file_ops *file_ops = NULL;
struct ftrace_event_call **call, **start, **end;
start = mod->trace_events;
end = mod->trace_events + mod->num_trace_events;
- if (start == end)
- return;
-
- file_ops = trace_create_file_ops(mod);
- if (!file_ops)
- return;
-
for_each_event(call, start, end) {
__register_event(*call, mod);
- __add_event_to_tracers(*call, file_ops);
+ __add_event_to_tracers(*call);
}
}
static void trace_module_remove_events(struct module *mod)
{
- struct ftrace_module_file_ops *file_ops;
struct ftrace_event_call *call, *p;
bool clear_trace = false;
@@ -1864,16 +1784,6 @@ static void trace_module_remove_events(struct module *mod)
__trace_remove_event_call(call);
}
}
-
- /* Now free the file_operations */
- list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
- if (file_ops->mod == mod)
- break;
- }
- if (&file_ops->list != &ftrace_module_file_list) {
- list_del(&file_ops->list);
- kfree(file_ops);
- }
up_write(&trace_event_sem);
/*
@@ -1909,62 +1819,22 @@ static int trace_module_notify(struct notifier_block *self,
return 0;
}
-static int
-__trace_add_new_mod_event(struct ftrace_event_call *call,
- struct trace_array *tr,
- struct ftrace_module_file_ops *file_ops)
-{
- return __trace_add_new_event(call, tr,
- &file_ops->id, &file_ops->enable,
- &file_ops->filter, &file_ops->format);
-}
-
#else
-static inline struct ftrace_module_file_ops *
-find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
-{
- return NULL;
-}
static inline int trace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
return 0;
}
-static inline int
-__trace_add_new_mod_event(struct ftrace_event_call *call,
- struct trace_array *tr,
- struct ftrace_module_file_ops *file_ops)
-{
- return -ENODEV;
-}
#endif /* CONFIG_MODULES */
/* Create a new event directory structure for a trace directory. */
static void
__trace_add_event_dirs(struct trace_array *tr)
{
- struct ftrace_module_file_ops *file_ops = NULL;
struct ftrace_event_call *call;
int ret;
list_for_each_entry(call, &ftrace_events, list) {
- if (call->mod) {
- /*
- * Directories for events by modules need to
- * keep module ref counts when opened (as we don't
- * want the module to disappear when reading one
- * of these files). The file_ops keep account of
- * the module ref count.
- */
- file_ops = find_ftrace_file_ops(file_ops, call->mod);
- if (!file_ops)
- continue; /* Warn? */
- ret = __trace_add_new_mod_event(call, tr, file_ops);
- if (ret < 0)
- pr_warning("Could not create directory for event %s\n",
- call->name);
- continue;
- }
ret = __trace_add_new_event(call, tr,
&ftrace_event_id_fops,
&ftrace_enable_fops,
@@ -2322,21 +2192,16 @@ __trace_remove_event_dirs(struct trace_array *tr)
remove_event_file_dir(file);
}
-static void
-__add_event_to_tracers(struct ftrace_event_call *call,
- struct ftrace_module_file_ops *file_ops)
+static void __add_event_to_tracers(struct ftrace_event_call *call)
{
struct trace_array *tr;
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
- if (file_ops)
- __trace_add_new_mod_event(call, tr, file_ops);
- else
- __trace_add_new_event(call, tr,
- &ftrace_event_id_fops,
- &ftrace_enable_fops,
- &ftrace_event_filter_fops,
- &ftrace_event_format_fops);
+ __trace_add_new_event(call, tr,
+ &ftrace_event_id_fops,
+ &ftrace_enable_fops,
+ &ftrace_event_filter_fops,
+ &ftrace_event_format_fops);
}
}
--
1.5.5.1
--
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