one of its functions results in a segmentation fault. The module-unload
functions must therefore cancel any delayed calls to loadable-module
functions, for example, any outstanding mod_timer() must be dealt
-with via del_timer_sync() or similar.
+with via timer_delete_sync() or similar.
Unfortunately, there is no way to cancel an RCU callback; once you
invoke call_rcu(), the callback function is eventually going to be
static void __exit test_exit(void)
{
- del_timer_sync(&test_timer);
+ timer_delete_sync(&test_timer);
}
module_init(test_init);
while (list) {
struct foo *next = list->next;
- del_timer(&list->timer);
+ timer_delete(&list->timer);
kfree(list);
list = next;
}
the element (which has already been freed!).
This can be avoided by checking the result of
-del_timer(): if it returns 1, the timer has been deleted.
+timer_delete(): if it returns 1, the timer has been deleted.
If 0, it means (in this case) that it is currently running, so we can
do::
while (list) {
struct foo *next = list->next;
- if (!del_timer(&list->timer)) {
+ if (!timer_delete(&list->timer)) {
/* Give timer a chance to delete this */
spin_unlock_bh(&list_lock);
goto retry;
Another common problem is deleting timers which restart themselves (by
calling add_timer() at the end of their timer function).
Because this is a fairly common case which is prone to races, you should
-use del_timer_sync() (``include/linux/timer.h``) to
-handle this case.
+use timer_delete_sync() (``include/linux/timer.h``) to handle this case.
Locking Speed
=============
- kfree()
-- add_timer() and del_timer()
+- add_timer() and timer_delete()
Mutex API reference
===================
was not really a win, due to the different data structures. Also, the
hrtimer functions now have clearer behavior and clearer names - such as
hrtimer_try_to_cancel() and hrtimer_cancel() [which are roughly
-equivalent to del_timer() and del_timer_sync()] - so there's no direct
+equivalent to timer_delete() and timer_delete_sync()] - so there's no direct
1:1 mapping between them on the algorithmic level, and thus no real
potential for code sharing either.
while (list) {
struct foo *next = list->next;
- del_timer(&list->timer);
+ timer_delete(&list->timer);
kfree(list);
list = next;
}
di eliminare il suo oggetto (che però è già stato eliminato).
Questo può essere evitato controllando il valore di ritorno di
-del_timer(): se ritorna 1, il temporizzatore è stato già
+timer_delete(): se ritorna 1, il temporizzatore è stato già
rimosso. Se 0, significa (in questo caso) che il temporizzatore è in
esecuzione, quindi possiamo fare come segue::
while (list) {
struct foo *next = list->next;
- if (!del_timer(&list->timer)) {
+ if (!timer_delete(&list->timer)) {
/* Give timer a chance to delete this */
spin_unlock_bh(&list_lock);
goto retry;
Un altro problema è l'eliminazione dei temporizzatori che si riavviano
da soli (chiamando add_timer() alla fine della loro esecuzione).
Dato che questo è un problema abbastanza comune con una propensione
-alle corse critiche, dovreste usare del_timer_sync()
+alle corse critiche, dovreste usare timer_delete_sync()
(``include/linux/timer.h``) per gestire questo caso.
Velocità della sincronizzazione
- kfree()
-- add_timer() e del_timer()
+- add_timer() e timer_delete()
Riferimento per l'API dei Mutex
===============================
static void __exit test_exit(void)
{
- del_timer_sync(&test_timer);
+ timer_delete_sync(&test_timer);
}
module_init(test_init);