From: Oleg Nesterov 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. Link: http://lkml.kernel.org/r/20130731173132.GA31033@redhat.com Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 153 +++---------------------------------------- 1 file changed, 9 insertions(+), 144 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 29a7ebc..2ec8273 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1683,8 +1683,7 @@ __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) @@ -1695,7 +1694,7 @@ 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); @@ -1769,100 +1768,21 @@ 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; @@ -1874,16 +1794,6 @@ 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); /* @@ -1919,62 +1829,22 @@ 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, @@ -2332,21 +2202,16 @@ __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); } } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/