Title: reply_thr_get() / reply_thr_put() / udp

reply_thr_get() calls (indirectly) sr_get_userdata(), which reports to the file system (FS) whether a previous operation requested by a process was successful. reply, reply_thr_get()'s second parameter, indicates whether the previous operation was successful.

After sending the message to the FS, sr_get_userdata() processes the messages in the write or ioctl queue.

reply_thr_put() does nearly the same thing as reply_thr_get(). However, instead of reporting whether write and ioctl operations were successful, reply_thr_put() reports on read and ioctl operations.