tracing/uprobes: Support multibuffer and soft-mode disabling

This is sixth version of uprobes-based dynamic events multibuffer and soft-mode disabling support work.

v5 -> v6:
- change list_for_each_entry to list_for_each_entry_rcu in uprobe_trace_func and uretprobe_trace_func, found by Namhyung Kim.

v4-> v5 (suggested by Oleg and Masami):
- code simply in probe_event_enable
- use list_del to replace list_del_rcu in probe_event_enable
- don't remove is_trace_uprobe_enabled() checking in probe_event_disable (I will check this later to figure out is it safe to remove that checking)

v3 -> v4:
- use "bool enabled = is_trace_uprobe_enabled(tu);", suggested by Oleg.
- use list_add_tail_rcu instead of list_add_rcu, suggested by Masami.
- fix the error handling in probe_event_enable, found by Srikar.

v3:
- separate soft-mode disabling patch from multibuffer support patch.
- fix some comments
- coding style trivial change
- fix flags race in probe_event_disable

zhangwei(Jovi) (2):
tracing/uprobes: Support ftrace_event_file base multibuffer tracing/uprobes: Support soft-mode disabling

 kernel/trace/trace_uprobe.c |  122 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 103 insertions(+), 19 deletions(-)

1.7.9.7