2003-11-25 21:52:10

by Frederic Rossi

Subject: [PATCH] AEM v0.5.1, linux-2.6.0-test9

AEM is an extension providing a native support for asynchronous events
in the Linux kernel. Below a patch for the previous v0.5 fixes
some issues when event handlers are forked.

Package: mod_aem-2.6
Version: v0.5.1

Modules+patches at:
http://sourceforge.net/projects/aem

Changelog:
* Fix the forked events termination procedure


Frederic





Index: aem/module/2.6.0-test9/aem-core/src/kernel/events.c
diff -u aem/module/2.6.0-test9/aem-core/src/kernel/events.c:1.1 aem/module/2.6.0-test9/aem-core/src/kernel/events.c:1.4
--- aem/module/2.6.0-test9/aem-core/src/kernel/events.c:1.1 Tue Nov 18 08:10:40 2003
+++ aem/module/2.6.0-test9/aem-core/src/kernel/events.c Mon Nov 24 07:54:03 2003
@@ -366,13 +377,12 @@
REMOVE_LINKS (task);
task->parent = task->real_parent = adopter;
SET_LINKS (task);
-
+
+ /* Post SIGCHLD */
spin_lock (&adopter->sighand->siglock);
sigaddset (&adopter->pending.signal, SIGCHLD);
recalc_sigpending_tsk (adopter);
spin_unlock (&adopter->sighand->siglock);
-
- wake_up_process (adopter);
}

void forget_child (struct task_struct *task)
@@ -420,46 +430,61 @@
* it is destroyed here.
*/
unsigned long jflags;
- struct event_struct *evc = task->cloner;
+ struct event_struct *evc;
struct task_struct *root;

- root = evc->root;
+ if (task->parent->pid == 1)
+ /* The parent has exited */
+ goto cleanup_events;
+
+ /* This is the event cloner... */
+ evc = task->cloner;
+
+ /* If the process is present, the event is still present too */
+ root = task->parent;
+ if (evc->root != root)
+ /* Sanity check */
+ goto cleanup_events;

if (get_task (root)) {
- local_bh_disable ();
- spin_lock (&evc->lock);
+ unsigned long flags;

- jflags = (evc->jargs)? evc->jargs->flags: 0;
+ local_irq_save (flags);
+ spin_lock (&evc->lock);

- if (jflags && ((jflags & EVF_FORK) || (jflags & EVF_CAPSULE))) {
+ jflags = (evc->jargs)? evc->jargs->flags: 0;
+
+ if (jflags && ((jflags & EVF_FORK) || (jflags & EVF_CAPSULE))) {
struct job_struct *job = job_lookup (evc->jid);

- local_bh_enable ();
- __event_dtor (evc);
- local_bh_disable ();
+ /* Called with irq disabled -- will be changed */
+ __event_dtor (evc);

- if (jflags & EVF_NOCLDWAIT)
- __forget_child (task);
+ if (jflags & EVF_NOCLDWAIT) {
+ __forget_child (task);
+ wake_up_process (capm);
+ }

- if (jflags & EVF_ONESHOT || (job && job->shutdown == JOB_SHUTDOWN)) {
- __events_remove (evc, job);
- kfree (evc);
- goto cont;
+ if (jflags & EVF_ONESHOT || (job && job->shutdown == JOB_SHUTDOWN)) {
+ __events_remove (evc, job);
+ kfree (evc);
+ goto cont;
+ }
+ }
+ else {
+ /* The event has probably been removed by the user */
+ __forget_child (task);
+ wake_up_process (capm);
}
- }
- else {
- /* The event has probably been removed by the user */
- __forget_child (task);
- }

- spin_unlock (&evc->lock);
- cont:
- put_task (root);
- local_bh_enable ();
+ spin_unlock (&evc->lock);
+ cont:
+ local_irq_restore (flags);
+ put_task (root);
}
}

-again:
+cleanup_events:
spin_lock_irq (&task->evlock);
list_for_each (curr, &task->events) {

@@ -481,7 +506,7 @@
job = job_hash_find (ev->jid);
__events_remove (ev, job);
kfree (ev);
- goto again;
+ goto cleanup_events;
}

list_del_init (&task->events);