diff --git a/include/linux/trace.h b/include/linux/trace.h index 36d255d66f88..c115a5d2269f 100644 --- a/include/linux/trace.h +++ b/include/linux/trace.h @@ -3,6 +3,9 @@ #define _LINUX_TRACE_H #ifdef CONFIG_TRACING + +#define TRACE_EXPORT_FUNCTION BIT(0) + /* * The trace export - an export of Ftrace output. The trace_export * can process traces and export them to a registered destination as @@ -15,10 +18,12 @@ * next - pointer to the next trace_export * write - copy traces which have been delt with ->commit() to * the destination + * flags - which ftrace to be exported */ struct trace_export { struct trace_export __rcu *next; void (*write)(struct trace_export *, const void *, unsigned int); + int flags; }; int register_ftrace_export(struct trace_export *export); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f40d850ebabc..3ca121ad8728 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2744,33 +2744,37 @@ trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer, static void trace_process_export(struct trace_export *export, - struct ring_buffer_event *event) + struct ring_buffer_event *event, int flag) { struct trace_entry *entry; unsigned int size = 0; - entry = ring_buffer_event_data(event); - size = ring_buffer_event_length(event); - export->write(export, entry, size); + if (export->flags & flag) { + entry = ring_buffer_event_data(event); + size = ring_buffer_event_length(event); + export->write(export, entry, size); + } } static DEFINE_MUTEX(ftrace_export_lock); static struct trace_export __rcu *ftrace_exports_list __read_mostly; -static DEFINE_STATIC_KEY_FALSE(ftrace_exports_enabled); +static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled); -static inline void ftrace_exports_enable(void) +static inline void ftrace_exports_enable(struct trace_export *export) { - static_branch_enable(&ftrace_exports_enabled); + if (export->flags & TRACE_EXPORT_FUNCTION) + static_branch_inc(&trace_function_exports_enabled); } -static inline void ftrace_exports_disable(void) +static inline void ftrace_exports_disable(struct trace_export *export) { - static_branch_disable(&ftrace_exports_enabled); + if (export->flags & TRACE_EXPORT_FUNCTION) + static_branch_dec(&trace_function_exports_enabled); } -static void ftrace_exports(struct ring_buffer_event *event) +static void ftrace_exports(struct ring_buffer_event *event, int flag) { struct trace_export *export; @@ -2778,7 +2782,7 @@ static void ftrace_exports(struct ring_buffer_event *event) export = rcu_dereference_raw_check(ftrace_exports_list); while (export) { - trace_process_export(export, event); + trace_process_export(export, event, flag); export = rcu_dereference_raw_check(export->next); } @@ -2818,8 +2822,7 @@ rm_trace_export(struct trace_export **list, struct trace_export *export) static inline void add_ftrace_export(struct trace_export **list, struct trace_export *export) { - if (*list == NULL) - ftrace_exports_enable(); + ftrace_exports_enable(export); add_trace_export(list, export); } @@ -2830,8 +2833,7 @@ rm_ftrace_export(struct trace_export **list, struct trace_export *export) int ret; ret = rm_trace_export(list, export); - if (*list == NULL) - ftrace_exports_disable(); + ftrace_exports_disable(export); return ret; } @@ -2884,8 +2886,8 @@ trace_function(struct trace_array *tr, entry->parent_ip = parent_ip; if (!call_filter_check_discard(call, entry, buffer, event)) { - if (static_branch_unlikely(&ftrace_exports_enabled)) - ftrace_exports(event); + if (static_branch_unlikely(&trace_function_exports_enabled)) + ftrace_exports(event, TRACE_EXPORT_FUNCTION); __buffer_unlock_commit(buffer, event); } }