[libvirt] [PATCH 1/5] Add a read/write lock implementation

[Daniel P. Berrange]

On Thu, Jan 23, 2014 at 03:22:53PM +0200, Laine Stump wrote:
> On 01/23/2014 02:37 PM, Daniel P. Berrange wrote:
> > Add virRWLock backed up by a POSIX rwlock primitive
> >
> > Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
> > ---
> >  src/libvirt_private.syms    |  5 +++++
> >  src/util/virthread.h        | 10 ++++++++++
> >  src/util/virthreadpthread.c | 31 +++++++++++++++++++++++++++++++
> >  src/util/virthreadpthread.h |  4 ++++
> >  4 files changed, 50 insertions(+)
> >
> > diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> > index d1a58f9..eb91693 100644
> > --- a/src/libvirt_private.syms
> > +++ b/src/libvirt_private.syms
> > @@ -1816,6 +1816,11 @@ virMutexInitRecursive;
> >  virMutexLock;
> >  virMutexUnlock;
> >  virOnce;
> > +virRWLockInit;
> > +virRWLockDestroy;
> > +virRWLockRead;
> > +virRWLockWrite;
> > +virRWLockUnlock;
> 
> These are out of order.
> 
> >  virThreadCancel;
> >  virThreadCreate;
> >  virThreadID;
> > diff --git a/src/util/virthread.h b/src/util/virthread.h
> > index 84d3bdc..7015d60 100644
> > --- a/src/util/virthread.h
> > +++ b/src/util/virthread.h
> > @@ -28,6 +28,9 @@
> >  typedef struct virMutex virMutex;
> >  typedef virMutex *virMutexPtr;
> >  
> > +typedef struct virRWLock virRWLock;
> > +typedef virRWLock *virRWLockPtr;
> > +
> >  typedef struct virCond virCond;
> >  typedef virCond *virCondPtr;
> >  
> > @@ -89,6 +92,13 @@ void virMutexLock(virMutexPtr m);
> >  void virMutexUnlock(virMutexPtr m);
> >  
> >  
> > +int virRWLockInit(virRWLockPtr m) ATTRIBUTE_RETURN_CHECK;
> > +void virRWLockDestroy(virRWLockPtr m);
> > +
> > +void virRWLockRead(virRWLockPtr m);
> > +void virRWLockWrite(virRWLockPtr m);
> > +void virRWLockUnlock(virRWLockPtr m);
> > +
> 
> I was about to predict a build failure on Windows since you haven't
> defined these functions in virthreadwin32.c, but then realized you
> aren't yet calling them from anywhere, so the build will complete just fine.
> 
> It would reduce code motion a bit to swap this patch with patch 2, but
> functionally there's no difference.

FYI the reason I did it in this order, is to make it easier to
backport to the stable branches. eg on the stable branches I'd
want to skip patch 2, since that's going to require a gnulib
update too.

Daniel
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