From: Willy Tarreau <w@1wt.eu>
Date: Tue, 28 Sep 2021 06:58:49 +0000 (+0200)
Subject: MINOR: threads: make tg point to the current thread's group
X-Git-Tag: v2.5-dev9~11
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fc69e410e605677be567ee43464424ad9336840f;p=thirdparty%2Fhaproxy.git

MINOR: threads: make tg point to the current thread's group

A the "tg" thread-local variable now always points to the current
thread group. It's pre-initializd to the first one during boot and is
set to point to the thread's one by ha_set_tid(). This last one takes
care of checking whether the thread group was assigned or not because
it may be called during boot before threads are initialized.
---

diff --git a/include/haproxy/thread.h b/include/haproxy/thread.h
index 37808d9d78..14c88f0379 100644
--- a/include/haproxy/thread.h
+++ b/include/haproxy/thread.h
@@ -90,6 +90,7 @@ enum { tid = 0 };
 static inline void ha_set_tid(unsigned int tid)
 {
 	ti = &ha_thread_info[tid];
+	tg = ti->tg ? ti->tg : &ha_tgroup_info[0];
 	th_ctx = &ha_thread_ctx[tid];
 }
 
@@ -201,12 +202,17 @@ extern THREAD_LOCAL unsigned int tid;      /* The thread id */
 
 #define ha_sigmask(how, set, oldset)  pthread_sigmask(how, set, oldset)
 
-/* sets the thread ID and the TID bit for the current thread */
+/* sets the thread ID, TID bit and thread cfg/ctx pointers for the current
+ * thread. Since it may be called during early boot even before threads are
+ * initialized, we have to be extra careful about some fields which may still
+ * be null. For example tg may be null during a part of the boot.
+ */
 static inline void ha_set_tid(unsigned int data)
 {
 	tid     = data;
 	tid_bit = (1UL << tid);
 	ti      = &ha_thread_info[tid];
+	tg      = ti->tg ? ti->tg : &ha_tgroup_info[0];
 	th_ctx  = &ha_thread_ctx[tid];
 }