};
/**
+ * fcoe_percpu_thread_create() - Create a receive thread for an online cpu
+ * @cpu: cpu index for the online cpu
+ */
+static void fcoe_percpu_thread_create(unsigned int cpu)
+{
+ struct fcoe_percpu_s *p;
+ struct task_struct *thread;
+
+ p = &per_cpu(fcoe_percpu, cpu);
+
+ thread = kthread_create(fcoe_percpu_receive_thread,
+ (void *)p, "fcoethread/%d", cpu);
+
+ if (likely(!IS_ERR(p->thread))) {
+ kthread_bind(thread, cpu);
+ wake_up_process(thread);
+
+ spin_lock_bh(&p->fcoe_rx_list.lock);
+ p->thread = thread;
+ spin_unlock_bh(&p->fcoe_rx_list.lock);
+ }
+}
+
+/**
+ * fcoe_percpu_thread_destroy() - removes the rx thread for the given cpu
+ * @cpu: cpu index the rx thread is to be removed
+ *
+ * Destroys a per-CPU Rx thread. Any pending skbs are moved to the
+ * current CPU's Rx thread. If the thread being destroyed is bound to
+ * the CPU processing this context the skbs will be freed.
+ */
+static void fcoe_percpu_thread_destroy(unsigned int cpu)
+{
+ struct fcoe_percpu_s *p;
+ struct task_struct *thread;
+ struct page *crc_eof;
+ struct sk_buff *skb;
+#ifdef CONFIG_SMP
+ struct fcoe_percpu_s *p0;
+ unsigned targ_cpu = smp_processor_id();
+#endif /* CONFIG_SMP */
+
+ printk(KERN_DEBUG "fcoe: Destroying receive thread for CPU %d\n", cpu);
+
+ /* Prevent any new skbs from being queued for this CPU. */
+ p = &per_cpu(fcoe_percpu, cpu);
+ spin_lock_bh(&p->fcoe_rx_list.lock);
+ thread = p->thread;
+ p->thread = NULL;
+ crc_eof = p->crc_eof_page;
+ p->crc_eof_page = NULL;
+ p->crc_eof_offset = 0;
+ spin_unlock_bh(&p->fcoe_rx_list.lock);
+
+#ifdef CONFIG_SMP
+ /*
+ * Don't bother moving the skb's if this context is running
+ * on the same CPU that is having its thread destroyed. This
+ * can easily happen when the module is removed.
+ */
+ if (cpu != targ_cpu) {
+ p0 = &per_cpu(fcoe_percpu, targ_cpu);
+ spin_lock_bh(&p0->fcoe_rx_list.lock);
+ if (p0->thread) {
+ FC_DBG("Moving frames from CPU %d to CPU %d\n",
+ cpu, targ_cpu);
+
+ while ((skb = __skb_dequeue(&p->fcoe_rx_list)) != NULL)
+ __skb_queue_tail(&p0->fcoe_rx_list, skb);
+ spin_unlock_bh(&p0->fcoe_rx_list.lock);
+ } else {
+ /*
+ * The targeted CPU is not initialized and cannot accept
+ * new skbs. Unlock the targeted CPU and drop the skbs
+ * on the CPU that is going offline.
+ */
+ while ((skb = __skb_dequeue(&p->fcoe_rx_list)) != NULL)
+ kfree_skb(skb);
+ spin_unlock_bh(&p0->fcoe_rx_list.lock);
+ }
+ } else {
+ /*
+ * This scenario occurs when the module is being removed
+ * and all threads are being destroyed. skbs will continue
+ * to be shifted from the CPU thread that is being removed
+ * to the CPU thread associated with the CPU that is processing
+ * the module removal. Once there is only one CPU Rx thread it
+ * will reach this case and we will drop all skbs and later
+ * stop the thread.
+ */
+ spin_lock_bh(&p->fcoe_rx_list.lock);
+ while ((skb = __skb_dequeue(&p->fcoe_rx_list)) != NULL)
+ kfree_skb(skb);
+ spin_unlock_bh(&p->fcoe_rx_list.lock);
+ }
+#else
+ /*
+ * This a non-SMP scenario where the singluar Rx thread is
+ * being removed. Free all skbs and stop the thread.
+ */
+ spin_lock_bh(&p->fcoe_rx_list.lock);
+ while ((skb = __skb_dequeue(&p->fcoe_rx_list)) != NULL)
+ kfree_skb(skb);
+ spin_unlock_bh(&p->fcoe_rx_list.lock);
+#endif
+
+ if (thread)
+ kthread_stop(thread);
+
+ if (crc_eof)
+ put_page(crc_eof);
+}
+
+/**
+ * fcoe_cpu_callback() - fcoe cpu hotplug event callback
+ * @nfb: callback data block
+ * @action: event triggering the callback
+ * @hcpu: index for the cpu of this event
+ *
+ * This creates or destroys per cpu data for fcoe
+ *
+ * Returns NOTIFY_OK always.
+ */
+static int fcoe_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ unsigned cpu = (unsigned long)hcpu;
+
+ switch (action) {
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ FC_DBG("CPU %x online: Create Rx thread\n", cpu);
+ fcoe_percpu_thread_create(cpu);
+ break;
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ FC_DBG("CPU %x offline: Remove Rx thread\n", cpu);
+ fcoe_percpu_thread_destroy(cpu);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block fcoe_cpu_notifier = {
+ .notifier_call = fcoe_cpu_callback,
+};
+
+/**
* fcoe_rcv() - this is the fcoe receive function called by NET_RX_SOFTIRQ
* @skb: the receive skb
* @dev: associated net device
struct fc_frame_header *fh;
struct fcoe_percpu_s *fps;
unsigned short oxid;
- unsigned int cpu_idx;
+ unsigned int cpu = 0;
fc = container_of(ptype, struct fcoe_softc, fcoe_packet_type);
lp = fc->lp;
fr = fcoe_dev_from_skb(skb);
fr->fr_dev = lp;
fr->ptype = ptype;
- cpu_idx = 0;
#ifdef CONFIG_SMP
/*
* The incoming frame exchange id(oxid) is ANDed with num of online
- * cpu bits to get cpu_idx and then this cpu_idx is used for selecting
- * a per cpu kernel thread from fcoe_percpu. In case the cpu is
- * offline or no kernel thread for derived cpu_idx then cpu_idx is
- * initialize to first online cpu index.
+ * cpu bits to get cpu and then this cpu is used for selecting
+ * a per cpu kernel thread from fcoe_percpu.
*/
- cpu_idx = oxid & (num_online_cpus() - 1);
- if (!cpu_online(cpu_idx))
- cpu_idx = first_cpu(cpu_online_map);
-
+ cpu = oxid & (num_online_cpus() - 1);
#endif
- fps = &per_cpu(fcoe_percpu, cpu_idx);
-
+ fps = &per_cpu(fcoe_percpu, cpu);
spin_lock_bh(&fps->fcoe_rx_list.lock);
+ if (unlikely(!fps->thread)) {
+ /*
+ * The targeted CPU is not ready, let's target
+ * the first CPU now. For non-SMP systems this
+ * will check the same CPU twice.
+ */
+ FC_DBG("CPU is online, but no receive thread ready "
+ "for incoming skb- using first online CPU.\n");
+
+ spin_unlock_bh(&fps->fcoe_rx_list.lock);
+ cpu = first_cpu(cpu_online_map);
+ fps = &per_cpu(fcoe_percpu, cpu);
+ spin_lock_bh(&fps->fcoe_rx_list.lock);
+ if (!fps->thread) {
+ spin_unlock_bh(&fps->fcoe_rx_list.lock);
+ goto err;
+ }
+ }
+
+ /*
+ * We now have a valid CPU that we're targeting for
+ * this skb. We also have this receive thread locked,
+ * so we're free to queue skbs into it's queue.
+ */
__skb_queue_tail(&fps->fcoe_rx_list, skb);
if (fps->fcoe_rx_list.qlen == 1)
wake_up_process(fps->thread);
return -ENOMEM;
}
fps->crc_eof_page = page;
- WARN_ON(fps->crc_eof_offset != 0);
+ fps->crc_eof_offset = 0;
}
get_page(page);
static int __init fcoe_init(void)
{
unsigned int cpu;
+ int rc = 0;
struct fcoe_percpu_s *p;
INIT_LIST_HEAD(&fcoe_hostlist);
skb_queue_head_init(&p->fcoe_rx_list);
}
- /*
- * initialize per CPU interrupt thread
- */
- for_each_online_cpu(cpu) {
- p = &per_cpu(fcoe_percpu, cpu);
- p->thread = kthread_create(fcoe_percpu_receive_thread,
- (void *)p, "fcoethread/%d", cpu);
+ for_each_online_cpu(cpu)
+ fcoe_percpu_thread_create(cpu);
- /*
- * If there is no error then bind the thread to the CPU
- * and wake it up.
- */
- if (!IS_ERR(p->thread)) {
- kthread_bind(p->thread, cpu);
- wake_up_process(p->thread);
- } else {
- p->thread = NULL;
- }
- }
+ /* Initialize per CPU interrupt thread */
+ rc = register_hotcpu_notifier(&fcoe_cpu_notifier);
+ if (rc)
+ goto out_free;
- /*
- * setup link change notification
- */
+ /* Setup link change notification */
fcoe_dev_setup();
setup_timer(&fcoe_timer, fcoe_watchdog, 0);
fcoe_sw_init();
return 0;
+
+out_free:
+ for_each_online_cpu(cpu) {
+ fcoe_percpu_thread_destroy(cpu);
+ }
+
+ return rc;
}
module_init(fcoe_init);
{
unsigned int cpu;
struct fcoe_softc *fc, *tmp;
- struct fcoe_percpu_s *p;
- struct sk_buff *skb;
fcoe_dev_cleanup();
list_for_each_entry_safe(fc, tmp, &fcoe_hostlist, list)
fcoe_transport_release(fc->real_dev);
- for_each_possible_cpu(cpu) {
- p = &per_cpu(fcoe_percpu, cpu);
- if (p->thread) {
- kthread_stop(p->thread);
- spin_lock_bh(&p->fcoe_rx_list.lock);
- while ((skb = __skb_dequeue(&p->fcoe_rx_list)) != NULL)
- kfree_skb(skb);
- spin_unlock_bh(&p->fcoe_rx_list.lock);
- if (p->crc_eof_page)
- put_page(p->crc_eof_page);
- }
+ unregister_hotcpu_notifier(&fcoe_cpu_notifier);
+
+ for_each_online_cpu(cpu) {
+ fcoe_percpu_thread_destroy(cpu);
}
/* remove sw trasnport */
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff