sysdeps/unix/sysv/linux directory structure question

[Steve Ellcey <sellcey@caviumnetworks.com>]

I am looking at some of the consolidation patches that Yury Norov and
Adhemerval Zanella have submitted and I was wondering if anyone could
help clarify the structure of sysdeps/unix/sysv/linux for me.

Basically we have some functions defined directly in this directory and
there is also a wordsize-64 directory, presumably for <name>64 versions
of those functions.

But there is also a generic directory and some files (send.c) are
defined in the linux directory and in the linux/generic
directory.  Also the generic directory has a wordsize-32 subdirectory
(but not a wordsize-64 one).

So I have several questions.  What is the difference between
sysdeps/unix/sysv/linux and sysdeps/unix/sysv/linux/generic and why
are some files in one vs. the other vs. both?   Is generic only for 64-
bit kernels?  Is that why it has a wordsize-32 subdirectory?  Are
functions transitioning (or supposed to be transitioning) from one
directory to another?

I did look at the hierarchy convention in the glibc manual (D.2.1
Layout of the sysdeps Directory Hierarchy) but that did not help
me with these questions.

Steve Ellcey
sellcey@caviumnetworks.com