Changeset 1871118 in mainline for kernel/generic/src/udebug/udebug_ops.c

Timestamp:

2023-02-10T22:59:11Z (2 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

master, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

11d2c983

Parents:

daadfa6

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2023-02-10 22:53:12)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2023-02-10 22:59:11)

Message:

Make thread_t reference counted

This simplifies interaction between various locks and thread
lifespan, which simplifies things. For example, threads_lock can
now simply be a mutex protecting the global it was made for, and
nothing more.

File:

• kernel/generic/src/udebug/udebug_ops.c (modified) (3 diffs)

kernel/generic/src/udebug/udebug_ops.c

@@ -83 +83 @@
         mutex_lock(&TASK->udebug.lock);
 
-        /* thread_exists() must be called with threads_lock held */
-        irq_spinlock_lock(&threads_lock, true);
-
-        if (!thread_exists(thread)) {
-                irq_spinlock_unlock(&threads_lock, true);
+        thread = thread_try_get(thread);
+
+        if (!thread) {
                 mutex_unlock(&TASK->udebug.lock);
                 return ENOENT;
         }
 
-        /* thread->lock is enough to ensure the thread's existence */
-        irq_spinlock_exchange(&threads_lock, &thread->lock);
+        irq_spinlock_lock(&thread->lock, true);
 
         /* Verify that 'thread' is a userspace thread. */
@@ -111 +108 @@
         }
 
-        /*
-         * Since the thread has active == true, TASK->udebug.lock
-         * is enough to ensure its existence and that active remains
-         * true.
-         *
-         */
-        irq_spinlock_unlock(&thread->lock, true);
-
-        /* Only mutex TASK->udebug.lock left. */
-
         /* Now verify that the thread belongs to the current task. */
         if (thread->task != TASK) {
                 /* No such thread belonging this task */
+                irq_spinlock_unlock(&thread->lock, true);
                 mutex_unlock(&TASK->udebug.lock);
                 return ENOENT;
         }
+
+        irq_spinlock_unlock(&thread->lock, true);
+
+        /* Only mutex TASK->udebug.lock left. */
 
         /*
@@ -153 +145 @@
 {
         mutex_unlock(&thread->udebug.lock);
+
+        /* Drop reference from _thread_op_begin() */
+        thread_put(thread);
 }