rwlock for async application

[David Mozes <david.mozes@silk.us>]

Hi all,
I want to discuss some needs that I think need to address.
On async coding used mainly on networking and storage applications, how ever I believe on other applications as well, what we are doing is acquiring a lock on the application level, and then call to the OS/kernel for sending/writing
Callback instead of waitengin on blocking for the sending/writing to finish. After completing the OS, call the CB to release the transaction and the lock.
The problem is that the current glibc implumnation doesn't support taking and releasing the writer lock from different threads.

I think it needs to be address .
 Actually I did the folwing change:

index d3f36303bf..b1032cfa2a 100644
--- a/nptl/pthread_rwlock_unlock.c
+++ b/nptl/pthread_rwlock_unlock.c
@@ -36,8 +36,7 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
      because nobody else can have stored this value.  Also, if we are a
      reader, we will read from the wrunlock store with value 0 by the most
      recent writer because that writer happens-before us.  */
-  if (atomic_load_relaxed (&rwlock->__data.__cur_writer)
-      == THREAD_GETMEM (THREAD_SELF, tid))
+  if (atomic_load_relaxed (&rwlock->__data.__cur_writer))
       __pthread_rwlock_wrunlock (rwlock);
   else
     __pthread_rwlock_rdunlock (rwlock);


On the current unlock function and seems to working so far on heavy load  and 3k threads.

I believe it has some limitions and need farther review.and might be calling in different name,but I  think  it be good to have it.

Your thout?

Thx
David