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* thread.h (struct pthread_rwlock::RWLOCK_READER): Add counter n.

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* thread.cc (pthread_rwlock::rdlock): If a thread already owns a
	read lock, just count the number of locks for it, per SUSv4.
	(pthread_rwlock::tryrdlock): Ditto.
	(pthread_rwlock::unlock): If a thread has more than one concurrent
	read locks, just count down.
This commit is contained in:
Corinna Vinschen
2009-01-20 12:40:31 +00:00
parent 3787b37ef2
commit f8190b5705
3 changed files with 26 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
winsup/cygwin/ChangeLog
View File

@@ -1,3 +1,12 @@
2009-01-20 Corinna Vinschen <corinna@vinschen.de>
* thread.h (struct pthread_rwlock::RWLOCK_READER): Add counter n.
* thread.cc (pthread_rwlock::rdlock): If a thread already owns a
read lock, just count the number of locks for it, per SUSv4.
(pthread_rwlock::tryrdlock): Ditto.
(pthread_rwlock::unlock): If a thread has more than one concurrent
read locks, just count down.
2009-01-20 Corinna Vinschen <corinna@vinschen.de>
* autoload.cc (WSAIoctl): Reintroduce.

20
winsup/cygwin/thread.cc
View File

@@ -1227,9 +1227,13 @@ pthread_rwlock::rdlock ()
mtx.lock ();
if (lookup_reader (self))
reader = lookup_reader (self);
if (reader)
{
result = EDEADLK;
if (reader->n < ULONG_MAX)
++reader->n;
else
errno = EAGAIN;
goto DONE;
}
@@ -1252,6 +1256,7 @@ pthread_rwlock::rdlock ()
}
reader->thread = self;
reader->n = 1;
add_reader (reader);
DONE:
@@ -1272,10 +1277,15 @@ pthread_rwlock::tryrdlock ()
result = EBUSY;
else
{
struct RWLOCK_READER *reader = new struct RWLOCK_READER;
if (reader)
struct RWLOCK_READER *reader;
reader = lookup_reader (self);
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
@@ -1365,6 +1375,8 @@ pthread_rwlock::unlock ()
result = EPERM;
goto DONE;
}
if (--reader->n > 0)
goto DONE;
remove_reader (reader);
delete reader;

1
winsup/cygwin/thread.h
View File

@@ -556,6 +556,7 @@ public:
{
struct RWLOCK_READER *next;
pthread_t thread;
unsigned long n;
} *readers;
fast_mutex readers_mx;