| Message ID | 20240605180409.179520305@goodmis.org (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | ftrace: Clean up and comment code | expand |
On Wed, Jun 05, 2024 at 02:03:39PM -0400, Steven Rostedt wrote: > From: "Steven Rostedt (Google)" <rostedt@goodmis.org> > > Describe what ftrace_hash_move() does and add some more comments to some > other functions to make it easier to understand. > > Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Mark. > --- > kernel/trace/ftrace.c | 24 +++++++++++++++++++++++- > 1 file changed, 23 insertions(+), 1 deletion(-) > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index 83f23f8fc26d..ae1603e771c5 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -169,6 +169,7 @@ static inline void ftrace_ops_init(struct ftrace_ops *ops) > #endif > } > > +/* Call this function for when a callback filters on set_ftrace_pid */ > static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, > struct ftrace_ops *op, struct ftrace_regs *fregs) > { > @@ -1317,7 +1318,7 @@ static struct ftrace_hash *alloc_ftrace_hash(int size_bits) > return hash; > } > > - > +/* Used to save filters on functions for modules not loaded yet */ > static int ftrace_add_mod(struct trace_array *tr, > const char *func, const char *module, > int enable) > @@ -1429,6 +1430,7 @@ static struct ftrace_hash *__move_hash(struct ftrace_hash *src, int size) > return new_hash; > } > > +/* Move the @src entries to a newly allocated hash */ > static struct ftrace_hash * > __ftrace_hash_move(struct ftrace_hash *src) > { > @@ -1443,6 +1445,26 @@ __ftrace_hash_move(struct ftrace_hash *src) > return __move_hash(src, size); > } > > +/** > + * ftrace_hash_move - move a new hash to a filter and do updates > + * @ops: The ops with the hash that @dst points to > + * @enable: True if for the filter hash, false for the notrace hash > + * @dst: Points to the @ops hash that should be updated > + * @src: The hash to update @dst with > + * > + * This is called when an ftrace_ops hash is being updated and the > + * the kernel needs to reflect this. Note, this only updates the kernel > + * function callbacks if the @ops is enabled (not to be confused with > + * @enable above). If the @ops is enabled, its hash determines what > + * callbacks get called. This function gets called when the @ops hash > + * is updated and it requires new callbacks. > + * > + * On success the elements of @src is moved to @dst, and @dst is updated > + * properly, as well as the functions determined by the @ops hashes > + * are now calling the @ops callback function. > + * > + * Regardless of return type, @src should be freed with free_ftrace_hash(). > + */ > static int > ftrace_hash_move(struct ftrace_ops *ops, int enable, > struct ftrace_hash **dst, struct ftrace_hash *src) > -- > 2.43.0 > >
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 83f23f8fc26d..ae1603e771c5 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -169,6 +169,7 @@ static inline void ftrace_ops_init(struct ftrace_ops *ops) #endif } +/* Call this function for when a callback filters on set_ftrace_pid */ static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs) { @@ -1317,7 +1318,7 @@ static struct ftrace_hash *alloc_ftrace_hash(int size_bits) return hash; } - +/* Used to save filters on functions for modules not loaded yet */ static int ftrace_add_mod(struct trace_array *tr, const char *func, const char *module, int enable) @@ -1429,6 +1430,7 @@ static struct ftrace_hash *__move_hash(struct ftrace_hash *src, int size) return new_hash; } +/* Move the @src entries to a newly allocated hash */ static struct ftrace_hash * __ftrace_hash_move(struct ftrace_hash *src) { @@ -1443,6 +1445,26 @@ __ftrace_hash_move(struct ftrace_hash *src) return __move_hash(src, size); } +/** + * ftrace_hash_move - move a new hash to a filter and do updates + * @ops: The ops with the hash that @dst points to + * @enable: True if for the filter hash, false for the notrace hash + * @dst: Points to the @ops hash that should be updated + * @src: The hash to update @dst with + * + * This is called when an ftrace_ops hash is being updated and the + * the kernel needs to reflect this. Note, this only updates the kernel + * function callbacks if the @ops is enabled (not to be confused with + * @enable above). If the @ops is enabled, its hash determines what + * callbacks get called. This function gets called when the @ops hash + * is updated and it requires new callbacks. + * + * On success the elements of @src is moved to @dst, and @dst is updated + * properly, as well as the functions determined by the @ops hashes + * are now calling the @ops callback function. + * + * Regardless of return type, @src should be freed with free_ftrace_hash(). + */ static int ftrace_hash_move(struct ftrace_ops *ops, int enable, struct ftrace_hash **dst, struct ftrace_hash *src)