Author: shurd Date: Mon Oct 29 14:36:03 2018 New Revision: 339861 URL: https://svnweb.freebsd.org/changeset/base/339861
Log: Drain grouptaskqueue of the gtask before detaching it. taskqgroup_detach() would remove the task even if it was running or enqueued, which could lead to panics (see D17404). With this change, taskqgroup_detach() drains the task and sets a new flag which prevents the task from being scheduled again. I've added grouptask_block() and grouptask_unblock() to allow control over the flag from other locations as well. Reviewed by: Jeffrey Pieper <jeffrey.e.pie...@intel.com> MFC after: 1 week Sponsored by: Limelight Networks Differential Revision: https://reviews.freebsd.org/D17674 Modified: head/sys/kern/subr_gtaskqueue.c head/sys/sys/gtaskqueue.h Modified: head/sys/kern/subr_gtaskqueue.c ============================================================================== --- head/sys/kern/subr_gtaskqueue.c Mon Oct 29 14:06:20 2018 (r339860) +++ head/sys/kern/subr_gtaskqueue.c Mon Oct 29 14:36:03 2018 (r339861) @@ -51,6 +51,8 @@ __FBSDID("$FreeBSD$"); static MALLOC_DEFINE(M_GTASKQUEUE, "gtaskqueue", "Group Task Queues"); static void gtaskqueue_thread_enqueue(void *); static void gtaskqueue_thread_loop(void *arg); +static int task_is_running(struct gtaskqueue *queue, struct gtask *gtask); +static void gtaskqueue_drain_locked(struct gtaskqueue *queue, struct gtask *gtask); TASKQGROUP_DEFINE(softirq, mp_ncpus, 1); TASKQGROUP_DEFINE(config, 1, 1); @@ -183,6 +185,44 @@ gtaskqueue_free(struct gtaskqueue *queue) free(queue, M_GTASKQUEUE); } +/* + * Wait for all to complete, then prevent it from being enqueued + */ +void +grouptask_block(struct grouptask *grouptask) +{ + struct gtaskqueue *queue = grouptask->gt_taskqueue; + struct gtask *gtask = &grouptask->gt_task; + +#ifdef INVARIANTS + if (queue == NULL) { + gtask_dump(gtask); + panic("queue == NULL"); + } +#endif + TQ_LOCK(queue); + gtask->ta_flags |= TASK_NOENQUEUE; + gtaskqueue_drain_locked(queue, gtask); + TQ_UNLOCK(queue); +} + +void +grouptask_unblock(struct grouptask *grouptask) +{ + struct gtaskqueue *queue = grouptask->gt_taskqueue; + struct gtask *gtask = &grouptask->gt_task; + +#ifdef INVARIANTS + if (queue == NULL) { + gtask_dump(gtask); + panic("queue == NULL"); + } +#endif + TQ_LOCK(queue); + gtask->ta_flags &= ~TASK_NOENQUEUE; + TQ_UNLOCK(queue); +} + int grouptaskqueue_enqueue(struct gtaskqueue *queue, struct gtask *gtask) { @@ -197,6 +237,10 @@ grouptaskqueue_enqueue(struct gtaskqueue *queue, struc TQ_UNLOCK(queue); return (0); } + if (gtask->ta_flags & TASK_NOENQUEUE) { + TQ_UNLOCK(queue); + return (EAGAIN); + } STAILQ_INSERT_TAIL(&queue->tq_queue, gtask, ta_link); gtask->ta_flags |= TASK_ENQUEUED; TQ_UNLOCK(queue); @@ -378,6 +422,13 @@ gtaskqueue_cancel(struct gtaskqueue *queue, struct gta return (error); } +static void +gtaskqueue_drain_locked(struct gtaskqueue *queue, struct gtask *gtask) +{ + while ((gtask->ta_flags & TASK_ENQUEUED) || task_is_running(queue, gtask)) + TQ_SLEEP(queue, gtask, &queue->tq_mutex, PWAIT, "-", 0); +} + void gtaskqueue_drain(struct gtaskqueue *queue, struct gtask *gtask) { @@ -386,8 +437,7 @@ gtaskqueue_drain(struct gtaskqueue *queue, struct gtas WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__); TQ_LOCK(queue); - while ((gtask->ta_flags & TASK_ENQUEUED) || task_is_running(queue, gtask)) - TQ_SLEEP(queue, gtask, &queue->tq_mutex, PWAIT, "-", 0); + gtaskqueue_drain_locked(queue, gtask); TQ_UNLOCK(queue); } @@ -803,6 +853,7 @@ taskqgroup_detach(struct taskqgroup *qgroup, struct gr { int i; + grouptask_block(gtask); mtx_lock(&qgroup->tqg_lock); for (i = 0; i < qgroup->tqg_cnt; i++) if (qgroup->tqg_queue[i].tgc_taskq == gtask->gt_taskqueue) @@ -813,6 +864,7 @@ taskqgroup_detach(struct taskqgroup *qgroup, struct gr LIST_REMOVE(gtask, gt_list); mtx_unlock(&qgroup->tqg_lock); gtask->gt_taskqueue = NULL; + gtask->gt_task.ta_flags &= ~TASK_NOENQUEUE; } static void Modified: head/sys/sys/gtaskqueue.h ============================================================================== --- head/sys/sys/gtaskqueue.h Mon Oct 29 14:06:20 2018 (r339860) +++ head/sys/sys/gtaskqueue.h Mon Oct 29 14:36:03 2018 (r339861) @@ -52,7 +52,9 @@ int gtaskqueue_cancel(struct gtaskqueue *queue, struct void gtaskqueue_drain(struct gtaskqueue *queue, struct gtask *task); void gtaskqueue_drain_all(struct gtaskqueue *queue); -int grouptaskqueue_enqueue(struct gtaskqueue *queue, struct gtask *task); +void grouptask_block(struct grouptask *grouptask); +void grouptask_unblock(struct grouptask *grouptask); +int grouptaskqueue_enqueue(struct gtaskqueue *queue, struct gtask *task); void taskqgroup_attach(struct taskqgroup *qgroup, struct grouptask *grptask, void *uniq, int irq, const char *name); int taskqgroup_attach_cpu(struct taskqgroup *qgroup, struct grouptask *grptask, @@ -67,6 +69,7 @@ void taskqgroup_config_gtask_deinit(struct grouptask * #define TASK_ENQUEUED 0x1 #define TASK_SKIP_WAKEUP 0x2 +#define TASK_NOENQUEUE 0x4 #define GTASK_INIT(task, flags, priority, func, context) do { \ _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
