diff options
| -rw-r--r-- | drivers/scsi/fcoe/libfcoe.c | 246 |
1 files changed, 199 insertions, 47 deletions
diff --git a/drivers/scsi/fcoe/libfcoe.c b/drivers/scsi/fcoe/libfcoe.c index 648a2fc0427..951d2448ad6 100644 --- a/drivers/scsi/fcoe/libfcoe.c +++ b/drivers/scsi/fcoe/libfcoe.c @@ -81,6 +81,156 @@ static struct notifier_block fcoe_notifier = { }; /** + * 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 @@ -100,7 +250,7 @@ int fcoe_rcv(struct sk_buff *skb, struct net_device *dev, 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; @@ -140,25 +290,42 @@ int fcoe_rcv(struct sk_buff *skb, struct net_device *dev, 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); @@ -214,7 +381,7 @@ static int fcoe_get_paged_crc_eof(struct sk_buff *skb, int tlen) return -ENOMEM; } fps->crc_eof_page = page; - WARN_ON(fps->crc_eof_offset != 0); + fps->crc_eof_offset = 0; } get_page(page); @@ -1271,6 +1438,7 @@ EXPORT_SYMBOL_GPL(fcoe_libfc_config); static int __init fcoe_init(void) { unsigned int cpu; + int rc = 0; struct fcoe_percpu_s *p; INIT_LIST_HEAD(&fcoe_hostlist); @@ -1281,29 +1449,15 @@ static int __init fcoe_init(void) 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); @@ -1316,6 +1470,13 @@ static int __init fcoe_init(void) fcoe_sw_init(); return 0; + +out_free: + for_each_online_cpu(cpu) { + fcoe_percpu_thread_destroy(cpu); + } + + return rc; } module_init(fcoe_init); @@ -1328,8 +1489,6 @@ static void __exit fcoe_exit(void) { unsigned int cpu; struct fcoe_softc *fc, *tmp; - struct fcoe_percpu_s *p; - struct sk_buff *skb; fcoe_dev_cleanup(); @@ -1340,17 +1499,10 @@ static void __exit fcoe_exit(void) 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 */ |