From b75ef8b44b1cb95f5a26484b0e2fe37a63b12b44 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Wed, 10 Aug 2011 15:18:39 -0400 Subject: Tracepoint: Dissociate from module mutex Copy the information needed from struct module into a local module list held within tracepoint.c from within the module coming/going notifier. This vastly simplifies locking of tracepoint registration / unregistration, because we don't have to take the module mutex to register and unregister tracepoints anymore. Steven Rostedt ran into dependency problems related to modules mutex vs kprobes mutex vs ftrace mutex vs tracepoint mutex that seems to be hard to fix without removing this dependency between tracepoint and module mutex. (note: it should be investigated whether kprobes could benefit of being dissociated from the modules mutex too.) This also fixes module handling of tracepoint list iterators, because it was expecting the list to be sorted by pointer address. Given we have control on our own list now, it's OK to sort this list which has tracepoints as its only purpose. The reason why this sorting is required is to handle the fact that seq files (and any read() operation from user-space) cannot hold the tracepoint mutex across multiple calls, so list entries may vanish between calls. With sorting, the tracepoint iterator becomes usable even if the list don't contain the exact item pointed to by the iterator anymore. Signed-off-by: Mathieu Desnoyers Acked-by: Jason Baron CC: Ingo Molnar CC: Lai Jiangshan CC: Peter Zijlstra CC: Thomas Gleixner CC: Masami Hiramatsu Link: http://lkml.kernel.org/r/20110810191839.GC8525@Krystal Signed-off-by: Steven Rostedt --- include/linux/tracepoint.h | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) (limited to 'include/linux/tracepoint.h') diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index d530a4460a0b..df0a779c1bbd 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -54,8 +54,18 @@ extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe, void *data); extern void tracepoint_probe_update_all(void); +#ifdef CONFIG_MODULES +struct tp_module { + struct list_head list; + unsigned int num_tracepoints; + struct tracepoint * const *tracepoints_ptrs; +}; +#endif /* CONFIG_MODULES */ + struct tracepoint_iter { - struct module *module; +#ifdef CONFIG_MODULES + struct tp_module *module; +#endif /* CONFIG_MODULES */ struct tracepoint * const *tracepoint; }; @@ -63,8 +73,6 @@ extern void tracepoint_iter_start(struct tracepoint_iter *iter); extern void tracepoint_iter_next(struct tracepoint_iter *iter); extern void tracepoint_iter_stop(struct tracepoint_iter *iter); extern void tracepoint_iter_reset(struct tracepoint_iter *iter); -extern int tracepoint_get_iter_range(struct tracepoint * const **tracepoint, - struct tracepoint * const *begin, struct tracepoint * const *end); /* * tracepoint_synchronize_unregister must be called between the last tracepoint @@ -78,17 +86,6 @@ static inline void tracepoint_synchronize_unregister(void) #define PARAMS(args...) args -#ifdef CONFIG_TRACEPOINTS -extern -void tracepoint_update_probe_range(struct tracepoint * const *begin, - struct tracepoint * const *end); -#else -static inline -void tracepoint_update_probe_range(struct tracepoint * const *begin, - struct tracepoint * const *end) -{ } -#endif /* CONFIG_TRACEPOINTS */ - #endif /* _LINUX_TRACEPOINT_H */ /* -- cgit v1.2.2