* runtime/transport/transport.c (_stp_get_root_dir): No longer
  locks/unlocks the transport directory.
  (_stp_remove_root_dir): Ditto.
  (_stp_transport_fs_init): Locks and unlocks the transport directory.
  Ensures that the root directory can't be deleted between calling
  _stp_get_root_dir() and creating the module dir.
  (_stp_transport_fs_close): Locks and unlocks the transport directory.

* runtime/task_finder_vma.c (stap_remove_vma_map_info): Return negative
  status on failure.
  (stap_find_vma_map_info): Likewise.
  (stap_find_vma_map_info_user): New function.
  (stap_drop_vma_maps): New function.
* runtime/sym.h (addr): Renamed to static_addr, to store addresses for
  sections which are always mapped at the same address.
  (_stp_module_relocate): Add extra struct task_struct *tsk argument.
* runtime/sym.c (_stp_tf_exec_cb): New callback, calls stap_drop_vma_maps.
  (_stp_tf_mmap_cb): Don't store address in module.section, but call
  stap_add_vma_map_info() per tsk->group_leader for matched module.
  Don't register empty/null modules.
  (_stp_module_relocate): Take extra struct task_struct *tsk argument,
  cache last tsk used. Only use section->static_addr for none dynamic
  modules. Use stap_find_vma_map_info_user() to locate dynamic modules.
  (_stp_mod_sec_lookup): Add extra argument unsigned long *rel_addr to
  optionally store relative address when module/section found.
  (_stp_kallsyms_lookup): Use _stp_mod_sec_lookup to find relative address.
  (_stp_sym_init): Register _stp_tf_exec_cb in stap_task_finder_target.
  Add error check to see if task finder could be initialized.
* dwflpp.cxx (emit_address): Pass NULL for kernel/modules and current for
  user tasks to _stp_module_relocate.
* runtime/transport/symbols.c (_stp_do_relocation): Set new static_addr
  _stp_section field.
* runtime/unwind.c (adjustStartLoc): Take new struct task_struct *tsk
  argument and pass to stap_find_vma_map_info_user and _stp_module_relocate
  to find adjusted addr.
  (_stp_search_unwind_hdr): Pass through struct task_struct *tsk.
  (unwind_frame): Likewise.
* tapset/context-symbols.stp (probemod): Add NULL to _stp_mod_sec_lookup
  call to indicate we aren't interested in relative address.
* tapsets.cxx (dwarf_derived_probe_group::emit_module_init): Pass NULL to
  _stp_module_relocate to indicate kernel/module address.

* runtime/transport/transport.h: Removed extra declarations of
  _stp_transport_init() and _stp_transport_close().

We had a race where the probe setup could be called during/after the
probe shutdown in abnormal circumstances, which leads to kernel
callbacks still registered after module unload.  (BOOM)

Now the setup/shutdown activities and related flags are guarded by a
mutex, so we should have strict ordering.

* runtime/transport/transport.c (_stp_transport_mutex): New.
  (_stp_handle_start): Grab the mutex, and make sure we're not exiting.
  (_stp_cleanup_and_exit): Grab the mutex.
  (_stp_lock_inode, _stp_unlock_inode): Use kernel version for checking
  inode locking type.

* transport/control.c (*_cmd): Return -Ecodes rather than "-1" from
  file_operations callbacks.
* staprun/ctl.c (init_ctl_channel): Return distinct error codes.
* staprun/staprun.c (remove_module): Skip connection attempt to .ctl
  file; just do delete_module() with O_NONBLOCK.

* runtime/tranport/ring_buffer.c: Removed 'USE_ITERS' definition.

* staplog.c (get_rchan): Separated original relayfs code and current
  relayfs code.
  (get_rchan_buf): Ditto.
  (output_cpu_logs): Ditto.
  (get_rchan_addr): Handles original relayfs code detection.
  (setup_global_data): Looks for '_stp_relay_data' structure instead of
  '_stp_utt' structure.
  (open_output_file): Improved error message.
* runtime/transport/relay_v2.c: Rearranged struct _stp_relay_data_type to
  make things a bit easier for staplog.c.
* runtime/transport/relayfs.c: Ditto

* transport/symbols.c (_stp_do_relocation): Make msg static.

* runtime/transport/ring_buffer.c (_stp_event_to_user): Removed unneeded
  cast.
  (_stp_data_write_reserve): Ditto.
  (_stp_data_write_commit): Ditto.