| From 6bd0a4b29753570a2c20b61b5ad2c0068567b7b6 Mon Sep 17 00:00:00 2001 |
| From: Philip Withnall <pwithnall@endlessos.org> |
| Date: Mon, 16 Nov 2020 16:44:29 +0000 |
| Subject: [PATCH 25/29] 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 <pwithnall@endlessos.org> |
| |
| Helps: #600 |
| Upstream-Status: Backport [https://gitlab.gnome.org/GNOME/glib/-/merge_requests/1719] |
| --- |
| 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; |
| |
| -- |
| 2.30.1 |
| |