taskq - Fix SMP spinlock recursion

diff --git a/sys/kern/subr_taskqueue.c b/sys/kern/subr_taskqueue.c
index 8dda83a..8a2c710 100644 (file)
--- a/sys/kern/subr_taskqueue.c
+++ b/sys/kern/subr_taskqueue.c
@@ -66,6 +66,8 @@ struct taskqueue {
 #define        TQ_FLAGS_BLOCKED        (1 << 1)
 #define        TQ_FLAGS_PENDING        (1 << 2)
 
+static void taskqueue_run(struct taskqueue *queue, int lock_held);
+
 static __inline void
 TQ_LOCK_INIT(struct taskqueue *tq)
 {
@@ -133,11 +135,7 @@ taskqueue_free(struct taskqueue *queue)
 {
        TQ_LOCK(queue);
        queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
-       TQ_UNLOCK(queue);
-
-       taskqueue_run(queue);
-
-       TQ_LOCK(queue);
+       taskqueue_run(queue, 1);
        taskqueue_terminate(queue->tq_threads, queue);
        TQ_UNLOCK(queue);
 
@@ -251,12 +249,13 @@ taskqueue_unblock(struct taskqueue *queue)
 }
 
 void
-taskqueue_run(struct taskqueue *queue)
+taskqueue_run(struct taskqueue *queue, int lock_held)
 {
        struct task *task;
        int pending;
 
-       TQ_LOCK(queue);
+       if (lock_held == 0)
+               TQ_LOCK(queue);
        while (STAILQ_FIRST(&queue->tq_queue)) {
                /*
                 * Carefully remove the first task from the queue and
@@ -275,7 +274,8 @@ taskqueue_run(struct taskqueue *queue)
                queue->tq_running = NULL;
                wakeup(task);
        }
-       TQ_UNLOCK(queue);
+       if (lock_held == 0)
+               TQ_UNLOCK(queue);
 }
 
 void
@@ -296,13 +296,13 @@ taskqueue_swi_enqueue(void *context)
 static void
 taskqueue_swi_run(void *arg, void *frame)
 {
-       taskqueue_run(taskqueue_swi);
+       taskqueue_run(taskqueue_swi, 0);
 }
 
 static void
 taskqueue_swi_mp_run(void *arg, void *frame)
 {
-       taskqueue_run(taskqueue_swi_mp);
+       taskqueue_run(taskqueue_swi_mp, 0);
 }
 
 int
@@ -338,7 +338,7 @@ taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu,
                        cpu = i%ncpus;
 
                error = lwkt_create(taskqueue_thread_loop, tqp,
-                   &tq->tq_threads[i], NULL, TDF_STOPREQ | TDF_MPSAFE, cpu,
+                   &tq->tq_threads[i], NULL, TDF_STOPREQ, cpu,
                    "%s_%d", ktname, i);
                if (error) {
                        kprintf("%s: kthread_add(%s): error %d", __func__,
@@ -364,7 +364,7 @@ taskqueue_thread_loop(void *arg)
        tq = *tqp;
        TQ_LOCK(tq);
        while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
-               taskqueue_run(tq);
+               taskqueue_run(tq, 1);
                TQ_SLEEP(tq, tq, "tqthr");
        }
 
@@ -397,7 +397,6 @@ TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0,
         register_swi(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL));
 
 struct taskqueue *taskqueue_thread[MAXCPU];
-static struct thread *taskqueue_thread_td[MAXCPU];
 
 static void
 taskqueue_init(void)

diff --git a/sys/sys/taskqueue.h b/sys/sys/taskqueue.h
index d07d555..d31bee0 100644 (file)
--- a/sys/sys/taskqueue.h
+++ b/sys/sys/taskqueue.h
@@ -73,7 +73,6 @@ int   taskqueue_enqueue(struct taskqueue *queue, struct task *task);
 void   taskqueue_drain(struct taskqueue *queue, struct task *task);
 struct taskqueue *taskqueue_find(const char *name);
 void   taskqueue_free(struct taskqueue *queue);
-void   taskqueue_run(struct taskqueue *queue);
 void   taskqueue_block(struct taskqueue *queue);
 void   taskqueue_unblock(struct taskqueue *queue);