diff options
| -rw-r--r-- | kernel/trace/trace_events.c | 95 |
1 files changed, 88 insertions, 7 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index b92081588088..be4d3a437c17 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -770,7 +770,11 @@ event_subsystem_dir(const char *name, struct dentry *d_events) } static int -event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) +event_create_dir(struct ftrace_event_call *call, struct dentry *d_events, + const struct file_operations *id, + const struct file_operations *enable, + const struct file_operations *filter, + const struct file_operations *format) { struct dentry *entry; int ret; @@ -800,11 +804,11 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) if (call->regfunc) entry = trace_create_file("enable", 0644, call->dir, call, - &ftrace_enable_fops); + enable); if (call->id) entry = trace_create_file("id", 0444, call->dir, call, - &ftrace_event_id_fops); + id); if (call->define_fields) { ret = call->define_fields(); @@ -814,7 +818,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) return ret; } entry = trace_create_file("filter", 0644, call->dir, call, - &ftrace_event_filter_fops); + filter); } /* A trace may not want to export its format */ @@ -822,7 +826,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) return 0; entry = trace_create_file("format", 0444, call->dir, call, - &ftrace_event_format_fops); + format); return 0; } @@ -833,8 +837,60 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) event++) #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 * +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; struct dentry *d_events; @@ -852,14 +908,27 @@ static void trace_module_add_events(struct module *mod) /* The linker may leave blanks */ if (!call->name) continue; + + /* + * This module has events, create file ops for this module + * if not already done. + */ + if (!file_ops) { + file_ops = trace_create_file_ops(mod); + if (!file_ops) + return; + } call->mod = mod; list_add(&call->list, &ftrace_events); - event_create_dir(call, d_events); + event_create_dir(call, d_events, + &file_ops->id, &file_ops->enable, + &file_ops->filter, &file_ops->format); } } static void trace_module_remove_events(struct module *mod) { + struct ftrace_module_file_ops *file_ops; struct ftrace_event_call *call, *p; list_for_each_entry_safe(call, p, &ftrace_events, list) { @@ -874,6 +943,16 @@ static void trace_module_remove_events(struct module *mod) list_del(&call->list); } } + + /* 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); + } } static int trace_module_notify(struct notifier_block *self, @@ -954,7 +1033,9 @@ static __init int event_trace_init(void) if (!call->name) continue; list_add(&call->list, &ftrace_events); - event_create_dir(call, d_events); + event_create_dir(call, d_events, &ftrace_event_id_fops, + &ftrace_enable_fops, &ftrace_event_filter_fops, + &ftrace_event_format_fops); } ret = register_module_notifier(&trace_module_nb); |