[libvirt] [PATCH 1/13] Adding recursive locks
Daniel P. Berrange
berrange at redhat.com
Wed Mar 17 11:48:46 UTC 2010
On Thu, Mar 11, 2010 at 08:06:34AM -0500, Stefan Berger wrote:
> This patch adds recursive locks necessary due to the processing of
> network filter XML that can reference other network filters, including
> references that cause looks. Loops in the XML are prevented but their
> detection requires recursive locks.
>
> ---
> src/util/threads-pthread.c | 12 ++++++++++++
> src/util/threads-pthread.h | 1 +
> src/util/threads-win32.c | 5 +++++
> src/util/threads.h | 1 +
> 4 files changed, 19 insertions(+)
>
> Index: libvirt-acl/src/util/threads-pthread.c
> ===================================================================
> --- libvirt-acl.orig/src/util/threads-pthread.c
> +++ libvirt-acl/src/util/threads-pthread.c
> @@ -43,6 +43,18 @@ int virMutexInit(virMutexPtr m)
> return 0;
> }
>
> +int virRecursiveMutexInit(virMutexPtr m)
> +{
> + int ret;
> + pthread_mutexattr_init(&m->attr);
> + pthread_mutexattr_settype(&m->attr, PTHREAD_MUTEX_RECURSIVE);
> + if ((ret = pthread_mutex_init(&m->lock, &m->attr)) != 0) {
> + errno = ret;
> + return -1;
> + }
> + return 0;
> +}
> +
> void virMutexDestroy(virMutexPtr m)
> {
> pthread_mutex_destroy(&m->lock);
Minor point, I think it would be better to call it virMutexInitRecursive()
so we keep the standard virMutex prefix for naming convention
> Index: libvirt-acl/src/util/threads-pthread.h
> ===================================================================
> --- libvirt-acl.orig/src/util/threads-pthread.h
> +++ libvirt-acl/src/util/threads-pthread.h
> @@ -24,6 +24,7 @@
> #include <pthread.h>
>
> struct virMutex {
> + pthread_mutexattr_t attr;
> pthread_mutex_t lock;
> };
I don't think this is neccessary - the attributes are only used
at time of pthread_mutex_init() call, so don't need to be kept
around after that. Thus the 'pthread_mutexattr_t attr' could just
be a local variable in virRecursiveMutexInit().
>
> Index: libvirt-acl/src/util/threads.h
> ===================================================================
> --- libvirt-acl.orig/src/util/threads.h
> +++ libvirt-acl/src/util/threads.h
> @@ -38,6 +38,7 @@ int virThreadInitialize(void) ATTRIBUTE_
> void virThreadOnExit(void);
>
> int virMutexInit(virMutexPtr m) ATTRIBUTE_RETURN_CHECK;
> +int virRecursiveMutexInit(virMutexPtr m) ATTRIBUTE_RETURN_CHECK;
> void virMutexDestroy(virMutexPtr m);
>
> void virMutexLock(virMutexPtr m);
> Index: libvirt-acl/src/util/threads-win32.c
> ===================================================================
> --- libvirt-acl.orig/src/util/threads-win32.c
> +++ libvirt-acl/src/util/threads-win32.c
> @@ -76,6 +76,11 @@ int virMutexInit(virMutexPtr m)
> return 0;
> }
>
> +int virRecursiveMutexInit(virMutexPtr m)
> +{
> + return virMutexInit(m);
> +}
> +
> void virMutexDestroy(virMutexPtr m)
> {
> CloseHandle(m->lock);
Regards,
Daniel
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