From 6bd0a4b29753570a2c20b61b5ad2c0068567b7b6 Mon Sep 17 00:00:00 2001 From: Philip Withnall Date: Mon, 16 Nov 2020 16:44:29 +0000 Subject: [PATCH] gthread: Use g_atomic() primitives correctly in destructor list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In the Windows destructor list, consistently access `g_private_destructors` using atomic primitives. `g_atomic_pointer_compare_and_exchange()` should be equivalent to `InterlockedCompareExchangePointer()`, but is a bit more understandable in a general GLib context, and pairs with `g_atomic_pointer_get()`. (I can’t find a Windows API equivalent for that.) Signed-off-by: Philip Withnall Helps: #600 --- glib/gthread-win32.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/glib/gthread-win32.c b/glib/gthread-win32.c index 0c37dc6c1..20aca6fa1 100644 --- a/glib/gthread-win32.c +++ b/glib/gthread-win32.c @@ -301,7 +301,7 @@ struct _GPrivateDestructor GPrivateDestructor *next; }; -static GPrivateDestructor * volatile g_private_destructors; +static GPrivateDestructor *g_private_destructors; /* (atomic) prepend-only */ static CRITICAL_SECTION g_private_lock; static DWORD @@ -329,7 +329,7 @@ g_private_get_impl (GPrivate *key) g_thread_abort (errno, "malloc"); destructor->index = impl; destructor->notify = key->notify; - destructor->next = g_private_destructors; + destructor->next = g_atomic_pointer_get (&g_private_destructors); /* We need to do an atomic store due to the unlocked * access to the destructor list from the thread exit @@ -337,13 +337,14 @@ g_private_get_impl (GPrivate *key) * * It can double as a sanity check... */ - if (InterlockedCompareExchangePointer (&g_private_destructors, destructor, - destructor->next) != destructor->next) + if (!g_atomic_pointer_compare_and_exchange (&g_private_destructors, + destructor->next, + destructor)) g_thread_abort (0, "g_private_get_impl(1)"); } /* Ditto, due to the unlocked access on the fast path */ - if (InterlockedCompareExchangePointer (&key->p, impl, NULL) != NULL) + if (!g_atomic_pointer_compare_and_exchange (&key->p, NULL, impl)) g_thread_abort (0, "g_private_get_impl(2)"); } LeaveCriticalSection (&g_private_lock); @@ -635,7 +636,7 @@ g_thread_win32_thread_detach (void) */ dtors_called = FALSE; - for (dtor = g_private_destructors; dtor; dtor = dtor->next) + for (dtor = g_atomic_pointer_get (&g_private_destructors); dtor; dtor = dtor->next) { gpointer value;