staging: lustre: ptlrpc: use delayed_work in sec_gc

The garbage collection for security contexts currently
has a dedicated kthread which wakes up every 30 minutes
to discard old garbage.

Replace this with a simple delayed_work item on the
system work queue.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/ptlrpc/sec_gc.c b/drivers/staging/lustre/lustre/ptlrpc/sec_gc.c
index 48f1a72..2c8bad7 100644 (file)
--- a/drivers/staging/lustre/lustre/ptlrpc/sec_gc.c
+++ b/drivers/staging/lustre/lustre/ptlrpc/sec_gc.c
@@ -55,7 +55,6 @@ static spinlock_t sec_gc_list_lock;
 static LIST_HEAD(sec_gc_ctx_list);
 static spinlock_t sec_gc_ctx_list_lock;
 
-static struct ptlrpc_thread sec_gc_thread;
 static atomic_t sec_gc_wait_del = ATOMIC_INIT(0);
 
 void sptlrpc_gc_add_sec(struct ptlrpc_sec *sec)
@@ -139,86 +138,53 @@ static void sec_do_gc(struct ptlrpc_sec *sec)
        sec->ps_gc_next = ktime_get_real_seconds() + sec->ps_gc_interval;
 }
 
-static int sec_gc_main(void *arg)
-{
-       struct ptlrpc_thread *thread = arg;
-
-       unshare_fs_struct();
+static void sec_gc_main(struct work_struct *ws);
+static DECLARE_DELAYED_WORK(sec_gc_work, sec_gc_main);
 
-       /* Record that the thread is running */
-       thread_set_flags(thread, SVC_RUNNING);
-       wake_up(&thread->t_ctl_waitq);
-
-       while (1) {
-               struct ptlrpc_sec *sec;
+static void sec_gc_main(struct work_struct *ws)
+{
+       struct ptlrpc_sec *sec;
 
-               sec_process_ctx_list();
+       sec_process_ctx_list();
 again:
-               /* go through sec list do gc.
-                * FIXME here we iterate through the whole list each time which
-                * is not optimal. we perhaps want to use balanced binary tree
-                * to trace each sec as order of expiry time.
-                * another issue here is we wakeup as fixed interval instead of
-                * according to each sec's expiry time
+       /* go through sec list do gc.
+        * FIXME here we iterate through the whole list each time which
+        * is not optimal. we perhaps want to use balanced binary tree
+        * to trace each sec as order of expiry time.
+        * another issue here is we wakeup as fixed interval instead of
+        * according to each sec's expiry time
+        */
+       mutex_lock(&sec_gc_mutex);
+       list_for_each_entry(sec, &sec_gc_list, ps_gc_list) {
+               /* if someone is waiting to be deleted, let it
+                * proceed as soon as possible.
                 */
-               mutex_lock(&sec_gc_mutex);
-               list_for_each_entry(sec, &sec_gc_list, ps_gc_list) {
-                       /* if someone is waiting to be deleted, let it
-                        * proceed as soon as possible.
-                        */
-                       if (atomic_read(&sec_gc_wait_del)) {
-                               CDEBUG(D_SEC, "deletion pending, start over\n");
-                               mutex_unlock(&sec_gc_mutex);
-                               goto again;
-                       }
-
-                       sec_do_gc(sec);
+               if (atomic_read(&sec_gc_wait_del)) {
+                       CDEBUG(D_SEC, "deletion pending, start over\n");
+                       mutex_unlock(&sec_gc_mutex);
+                       goto again;
                }
-               mutex_unlock(&sec_gc_mutex);
-
-               /* check ctx list again before sleep */
-               sec_process_ctx_list();
-               wait_event_idle_timeout(thread->t_ctl_waitq,
-                                       thread_is_stopping(thread),
-                                       SEC_GC_INTERVAL * HZ);
 
-               if (thread_test_and_clear_flags(thread, SVC_STOPPING))
-                       break;
+               sec_do_gc(sec);
        }
+       mutex_unlock(&sec_gc_mutex);
 
-       thread_set_flags(thread, SVC_STOPPED);
-       wake_up(&thread->t_ctl_waitq);
-       return 0;
+       /* check ctx list again before sleep */
+       sec_process_ctx_list();
+       schedule_delayed_work(&sec_gc_work, SEC_GC_INTERVAL * HZ);
 }
 
 int sptlrpc_gc_init(void)
 {
-       struct task_struct *task;
-
        mutex_init(&sec_gc_mutex);
        spin_lock_init(&sec_gc_list_lock);
        spin_lock_init(&sec_gc_ctx_list_lock);
 
-       /* initialize thread control */
-       memset(&sec_gc_thread, 0, sizeof(sec_gc_thread));
-       init_waitqueue_head(&sec_gc_thread.t_ctl_waitq);
-
-       task = kthread_run(sec_gc_main, &sec_gc_thread, "sptlrpc_gc");
-       if (IS_ERR(task)) {
-               CERROR("can't start gc thread: %ld\n", PTR_ERR(task));
-               return PTR_ERR(task);
-       }
-
-       wait_event_idle(sec_gc_thread.t_ctl_waitq,
-                       thread_is_running(&sec_gc_thread));
+       schedule_delayed_work(&sec_gc_work, 0);
        return 0;
 }
 
 void sptlrpc_gc_fini(void)
 {
-       thread_set_flags(&sec_gc_thread, SVC_STOPPING);
-       wake_up(&sec_gc_thread.t_ctl_waitq);
-
-       wait_event_idle(sec_gc_thread.t_ctl_waitq,
-                       thread_is_stopped(&sec_gc_thread));
+       cancel_delayed_work_sync(&sec_gc_work);
 }