Now we only have one implementation of rwsem. Even though we still use
xadd to handle reader locking, we use cmpxchg for writer instead. So
the filename rwsem-xadd.c is not strictly correct. Also no one outside
of the rwsem code need to know the internal implementation other than
function prototypes for two internal functions that are called directly
from percpu-rwsem.c.

So the rwsem-xadd.c and rwsem.h files are now merged into rwsem.c in
the following order:

The rwsem.h file now contains only 2 function declarations for
__up_read() and __down_read().

This is a code relocation patch with no code change at all except
making __up_read() and __down_read() non-static functions so they
can be used by percpu-rwsem.c.

Suggested-by: Peter Zijlstra
Signed-off-by: Waiman Long
Signed-off-by: Peter Zijlstra (Intel)
Cc: Borislav Petkov
Cc: Davidlohr Bueso
Cc: H. Peter Anvin
Cc: Linus Torvalds
Cc: Thomas Gleixner
Cc: Tim Chen
Cc: Will Deacon
Cc: huang ying
Link: https://lkml.kernel.org/r/20190520205918.22251-5-longman@redhat.com
Signed-off-by: Ingo Molnar