[1/5] do not call g_thread_init() for glib >= 2.31

glib >= 2.31 always enables thread support and g_thread_supported()
is #defined to 1, there's no need to call g_thread_init() anymore,
and it definitely does not need to report error which never happens.
Keep code for old < 2.31 glibc anyway for now, just #ifdef it
differently.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
 coroutine-gthread.c |    7 ++-----
 util/osdep.c        |   21 +++++++++------------
 2 files changed, 11 insertions(+), 17 deletions(-)

On Tue, Apr 29, 2014 at 10:02:24AM +0400, Michael Tokarev wrote:
> glib >= 2.31 always enables thread support and g_thread_supported()
> is #defined to 1, there's no need to call g_thread_init() anymore,
> and it definitely does not need to report error which never happens.
> Keep code for old < 2.31 glibc anyway for now, just #ifdef it
> differently.

This looks good to me, ACK

> 
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
>  coroutine-gthread.c |    7 ++-----
>  util/osdep.c        |   21 +++++++++------------
>  2 files changed, 11 insertions(+), 17 deletions(-)
> 
> diff --git a/coroutine-gthread.c b/coroutine-gthread.c
> index d3e5b99..a61efe0 100644
> --- a/coroutine-gthread.c
> +++ b/coroutine-gthread.c
> @@ -115,14 +115,11 @@ static inline GThread *create_thread(GThreadFunc func, gpointer data)
>  
>  static void __attribute__((constructor)) coroutine_init(void)
>  {
> -    if (!g_thread_supported()) {
>  #if !GLIB_CHECK_VERSION(2, 31, 0)
> +    if (!g_thread_supported()) {
>          g_thread_init(NULL);
> -#else
> -        fprintf(stderr, "glib threading failed to initialize.\n");
> -        exit(1);
> -#endif
>      }
> +#endif
>  
>      init_coroutine_cond();
>  }
> diff --git a/util/osdep.c b/util/osdep.c
> index a9029f8..b2bd154 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -436,23 +436,20 @@ int socket_init(void)
>      return 0;
>  }
>  
> -/* Ensure that glib is running in multi-threaded mode */
> +#if !GLIB_CHECK_VERSION(2, 31, 0)
> +/* Ensure that glib is running in multi-threaded mode
> + * Old versions of glib require explicit initialization.  Failure to do
> + * this results in the single-threaded code paths being taken inside
> + * glib.  For example, the g_slice allocator will not be thread-safe
> + * and cause crashes.
> + */
>  static void __attribute__((constructor)) thread_init(void)
>  {
>      if (!g_thread_supported()) {
> -#if !GLIB_CHECK_VERSION(2, 31, 0)
> -        /* Old versions of glib require explicit initialization.  Failure to do
> -         * this results in the single-threaded code paths being taken inside
> -         * glib.  For example, the g_slice allocator will not be thread-safe
> -         * and cause crashes.
> -         */
> -        g_thread_init(NULL);
> -#else
> -        fprintf(stderr, "glib threading failed to initialize.\n");
> -        exit(1);
> -#endif
> +       g_thread_init(NULL);
>      }
>  }
> +#endif
>  
>  #ifndef CONFIG_IOVEC
>  /* helper function for iov_send_recv() */
> -- 
> 1.7.10.4
>

On Tue, Apr 29, 2014 at 10:02:24AM +0400, Michael Tokarev wrote:
> glib >= 2.31 always enables thread support and g_thread_supported()
> is #defined to 1, there's no need to call g_thread_init() anymore,
> and it definitely does not need to report error which never happens.
> Keep code for old < 2.31 glibc anyway for now, just #ifdef it
> differently.
> 
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
>  coroutine-gthread.c |    7 ++-----
>  util/osdep.c        |   21 +++++++++------------
>  2 files changed, 11 insertions(+), 17 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>