From 124af9f4b2b77b1510d88cfc8092c788d7e513c7 Mon Sep 17 00:00:00 2001
From: Eric Andersen <andersen@codepoet.org>
Date: Fri, 20 May 2005 19:02:51 +0000
Subject: Back out nptl changes, which for now will be done in
 branches/uClibc-nptl

---
 libpthread/nptl/DESIGN-rwlock.txt | 113 --------------------------------------
 1 file changed, 113 deletions(-)
 delete mode 100644 libpthread/nptl/DESIGN-rwlock.txt

(limited to 'libpthread/nptl/DESIGN-rwlock.txt')

diff --git a/libpthread/nptl/DESIGN-rwlock.txt b/libpthread/nptl/DESIGN-rwlock.txt
deleted file mode 100644
index 810d1b8f3..000000000
--- a/libpthread/nptl/DESIGN-rwlock.txt
+++ /dev/null
@@ -1,113 +0,0 @@
-Reader Writer Locks pseudocode
-==============================
-
-	pthread_rwlock_rdlock(pthread_rwlock_t *rwlock);
-	pthread_rwlock_unlock(pthread_rwlock_t *rwlock);
-	pthread_rwlock_wrlock(pthread_rwlock_t *rwlock);
-
-struct pthread_rwlock_t {
-
-   unsigned int lock:
-         - internal mutex
-
-   unsigned int writers_preferred;
-         - locking mode: 0 recursive, readers preferred
-                         1 nonrecursive, writers preferred
-
-   unsigned int readers;
-         - number of read-only references various threads have
-
-   pthread_t writer;
-         - descriptor of the writer or 0
-
-   unsigned int readers_wakeup;
-         - 'all readers should wake up' futex.
-
-   unsigned int writer_wakeup;
-         - 'one writer should wake up' futex.
-
-   unsigned int nr_readers_queued;
-         - number of readers queued up.
-
-   unsigned int nr_writers_queued;
-         - number of writers queued up.
-}
-
-pthread_rwlock_rdlock(pthread_rwlock_t *rwlock)
-{
-  lll_lock(rwlock->lock);
-  for (;;) {
-    if (!rwlock->writer && (!rwlock->nr_writers_queued ||
-					!rwlock->writers_preferred))
-        break;
-
-    rwlock->nr_readers_queued++;
-    val = rwlock->readers_wakeup;
-    lll_unlock(rwlock->lock);
-
-    futex_wait(&rwlock->readers_wakeup, val)
-
-    lll_lock(rwlock->lock);
-    rwlock->nr_readers_queued--;
-  }
-  rwlock->readers++;
-  lll_unlock(rwlock->lock);
-}
-
-pthread_rwlock_tryrdlock(pthread_rwlock_t *rwlock)
-{
-  int result = EBUSY;
-  lll_lock(rwlock->lock);
-  if (!rwlock->writer && (!rwlock->nr_writers_queued ||
-					!rwlock->writers_preferred))
-    rwlock->readers++;
-  lll_unlock(rwlock->lock);
-  return result;
-}
-
-pthread_rwlock_wrlock(pthread_rwlock_t *rwlock)
-{
-  lll_lock(rwlock->lock);
-  for (;;) {
-    if (!rwlock->writer && !rwlock->readers)
-       break;
-
-    rwlock->nr_writers_queued++;
-    val = rwlock->writer_wakeup;
-    lll_unlock(rwlock->lock);
-
-    futex_wait(&rwlock->writer_wakeup, val);
-
-    lll_lock(rwlock->lock);
-    rwlock->nr_writers_queued--;
-  }
-  rwlock->writer = pthread_self();
-  lll_unlock(rwlock->lock);
-}
-
-pthread_rwlock_unlock(pthread_rwlock_t *rwlock)
-{
-  lll_lock(rwlock->lock);
-
-  if (rwlock->writer)
-    rwlock->writer = 0;
-  else
-    rwlock->readers--;
-
-  if (!rwlock->readers) {
-    if (rwlock->nr_writers_queued) {
-      ++rwlock->writer_wakeup;
-      lll_unlock(rwlock->lock);
-      futex_wake(&rwlock->writer_wakeup, 1);
-      return;
-    } else
-      if (rwlock->nr_readers_queued) {
-        ++rwlock->readers_wakeup;
-        lll_unlock(rwlock->lock);
-        futex_wake(&rwlock->readers_wakeup, MAX_INT);
-        return;
-      }
-  }
-
-  lll_unlock(rwlock->lock);
-}
-- 
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