From 8f3f61eb961322d7b50be81fbe51195565967738 Mon Sep 17 00:00:00 2001
From: Christopher Faylor <me@cgf.cx>
Date: Mon, 7 Jan 2013 16:01:10 +0000
Subject: [PATCH] * thread.cc (pthread_rwlock::add_reader): Perform new
 operation here and return pointer to allocated RWLOCK_READER structure.
 (pthread_rwlock::rdlock): Reorganize to reflect new add_reader functionality.
 (pthread_rwlock::tryrdlock): Ditto.  Remove unneeded call to lookup_reader().
 * thread.h (pthread_rwlock::RWLOCK_READER::RWLOCK_READER): New constructor.
 (pthread_rwlock::add_reader): Reflect new functionality.

---
 winsup/cygwin/ChangeLog | 12 ++++++++++++
 winsup/cygwin/thread.cc | 31 +++++++++++++------------------
 winsup/cygwin/thread.h  |  3 ++-
 3 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index ac6124745..1bdcdd9b5 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,15 @@
+2013-01-07  Christopher Faylor  <me.cygwin2013@cgf.cx>
+
+	* thread.cc (pthread_rwlock::add_reader): Perform new operation here
+	and return pointer to allocated RWLOCK_READER structure.
+	(pthread_rwlock::rdlock): Reorganize to reflect new add_reader
+	functionality.
+	(pthread_rwlock::tryrdlock): Ditto.  Remove unneeded call to
+	lookup_reader().
+	* thread.h (pthread_rwlock::RWLOCK_READER::RWLOCK_READER): New
+	constructor.
+	(pthread_rwlock::add_reader): Reflect new functionality.
+
 2013-01-03  Christopher Faylor  <me.cygwin2013@cgf.cx>
 
 	* globals.cc (exit_states): Renumber so that ES_EXIT_STARTING is first,
diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index ba3221cc9..3dd0255e5 100644
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -1391,8 +1391,9 @@ pthread_rwlock::rdlock ()
       goto DONE;
     }
 
-  reader = new struct RWLOCK_READER;
-  if (!reader)
+  if ((reader = add_reader ()))
+    ++reader->n;
+  else
     {
       result = EAGAIN;
       goto DONE;
@@ -1409,9 +1410,6 @@ pthread_rwlock::rdlock ()
       pthread_cleanup_pop (0);
     }
 
-  reader->thread = self;
-  reader->n = 1;
-  add_reader (reader);
 
  DONE:
   mtx.unlock ();
@@ -1427,21 +1425,15 @@ pthread_rwlock::tryrdlock ()
 
   mtx.lock ();
 
-  if (writer || waiting_writers || lookup_reader (self))
+  if (writer || waiting_writers)
     result = EBUSY;
   else
     {
-      struct RWLOCK_READER *reader;
-
-      reader = lookup_reader (self);
+      RWLOCK_READER *reader = lookup_reader (self);
+      if (!reader)
+	reader = add_reader ();
       if (reader && reader->n < ULONG_MAX)
 	++reader->n;
-      else if ((reader = new struct RWLOCK_READER))
-	{
-	  reader->thread = self;
-	  reader->n = 1;
-	  add_reader (reader);
-	}
       else
 	result = EAGAIN;
     }
@@ -1544,10 +1536,13 @@ pthread_rwlock::unlock ()
   return result;
 }
 
-void
-pthread_rwlock::add_reader (struct RWLOCK_READER *rd)
+pthread_rwlock::RWLOCK_READER *
+pthread_rwlock::add_reader ()
 {
-  List_insert (readers, rd);
+  RWLOCK_READER *rd = new RWLOCK_READER;
+  if (rd)
+    List_insert (readers, rd);
+  return rd;
 }
 
 void
diff --git a/winsup/cygwin/thread.h b/winsup/cygwin/thread.h
index a0412e1d0..1c7b7c62a 100644
--- a/winsup/cygwin/thread.h
+++ b/winsup/cygwin/thread.h
@@ -555,6 +555,7 @@ public:
     struct RWLOCK_READER *next;
     pthread_t thread;
     unsigned long n;
+    RWLOCK_READER (): next (NULL), thread (pthread::self ()), n (0) {}
   } *readers;
   fast_mutex readers_mx;
 
@@ -583,7 +584,7 @@ public:
 private:
   static List<pthread_rwlock> rwlocks;
 
-  void add_reader (struct RWLOCK_READER *rd);
+  RWLOCK_READER *add_reader ();
   void remove_reader (struct RWLOCK_READER *rd);
   struct RWLOCK_READER *lookup_reader (pthread_t thread);