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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/moduleparam.h>#include <linux/kernel.h>#include <linux/netdevice.h>#include <linux/etherdevice.h>#include <linux/string.h>#include <linux/if_arp.h>#include <linux/inetdevice.h>#include <linux/inet.h>#include <linux/interrupt.h>#include <linux/netpoll.h>#include <linux/sched.h>#include <linux/delay.h>#include <linux/rcupdate.h>#include <linux/workqueue.h>#include <linux/slab.h>#include <linux/export.h>#include <linux/if_vlan.h>#include <linux/udp.h>#include <net/tcp.h>#include <net/addrconf.h>#include <net/ndisc.h>#include <trace/events/napi.h>#include <linux/kconfig.h>
#define USEC_PER_POLL 50
/* * Cap on skbs parked in npinfo->txq while the device is busy. The queue * exists to ride out a transient stall; a producer that outruns the * device for longer than that must lose packets, not grow it without * bound. Checked without the queue lock, so the queue can overshoot * slightly. */#define NETPOLL_TXQ_MAX 1024
/* * carrier_timeout is netconsole-specific and only kept here to preserve the * netpoll.carrier_timeout module-parameter ABI. Its value is exposed to * netconsole through netpoll_get_carrier_timeout(). */static unsigned int carrier_timeout = 4;module_param(carrier_timeout, uint, 0644);
unsigned int netpoll_get_carrier_timeout(void){ return carrier_timeout;}EXPORT_SYMBOL_GPL(netpoll_get_carrier_timeout);
static netdev_tx_t netpoll_start_xmit(struct sk_buff *skb, struct net_device *dev, struct netdev_queue *txq){ netdev_tx_t status = NETDEV_TX_OK; netdev_features_t features;
features = netif_skb_features(skb);
if (skb_vlan_tag_present(skb) && !vlan_hw_offload_capable(features, skb->vlan_proto)) { skb = __vlan_hwaccel_push_inside(skb); if (unlikely(!skb)) { /* This is actually a packet drop, but we * don't want the code that calls this * function to try and operate on a NULL skb. */ goto out; } }
status = netdev_start_xmit(skb, dev, txq, false);
out: return status;}
static void queue_process(struct work_struct *work){ struct netpoll_info *npinfo = container_of(work, struct netpoll_info, tx_work.work); struct sk_buff *skb; unsigned long flags;
while ((skb = skb_dequeue(&npinfo->txq))) { struct net_device *dev = skb->dev; struct netdev_queue *txq; unsigned int q_index;
if (!netif_device_present(dev) || !netif_running(dev)) { kfree_skb(skb); continue; }
local_irq_save(flags); /* check if skb->queue_mapping is still valid */ q_index = skb_get_queue_mapping(skb); if (unlikely(q_index >= dev->real_num_tx_queues)) { q_index = q_index % dev->real_num_tx_queues; skb_set_queue_mapping(skb, q_index); } txq = netdev_get_tx_queue(dev, q_index); HARD_TX_LOCK(dev, txq, smp_processor_id()); if (netif_xmit_frozen_or_stopped(txq) || !dev_xmit_complete(netpoll_start_xmit(skb, dev, txq))) { skb_queue_head(&npinfo->txq, skb); HARD_TX_UNLOCK(dev, txq); local_irq_restore(flags);
schedule_delayed_work(&npinfo->tx_work, HZ/10); return; } HARD_TX_UNLOCK(dev, txq); local_irq_restore(flags); }}
static int netif_local_xmit_active(struct net_device *dev){ int i;
for (i = 0; i < dev->num_tx_queues; i++) { struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
if (netif_tx_owned(txq, smp_processor_id())) return 1; }
return 0;}
static void poll_one_napi(struct napi_struct *napi){ int work;
/* If we set this bit but see that it has already been set, * that indicates that napi has been disabled and we need * to abort this operation */ if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state)) return;
/* We explicitly pass the polling call a budget of 0 to * indicate that we are clearing the Tx path only. */ work = napi->poll(napi, 0); WARN_ONCE(work, "%pS exceeded budget in poll\n", napi->poll); trace_napi_poll(napi, work, 0);
clear_bit(NAPI_STATE_NPSVC, &napi->state);}
static void poll_napi(struct net_device *dev){ struct napi_struct *napi; int cpu = smp_processor_id();
list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) { if (cmpxchg(&napi->poll_owner, -1, cpu) == -1) { poll_one_napi(napi); smp_store_release(&napi->poll_owner, -1); } }}
void netpoll_poll_dev(struct net_device *dev){ struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo); const struct net_device_ops *ops;
/* Don't do any rx activity if the dev_lock mutex is held * the dev_open/close paths use this to block netpoll activity * while changing device state */ if (!ni || down_trylock(&ni->dev_lock)) return;
/* Some drivers will take the same locks in poll and xmit, * we can't poll if local CPU is already in xmit. */ if (!netif_running(dev) || netif_local_xmit_active(dev)) { up(&ni->dev_lock); return; }
ops = dev->netdev_ops; if (ops->ndo_poll_controller) ops->ndo_poll_controller(dev);
poll_napi(dev);
up(&ni->dev_lock);
netpoll_zap_completion_queue();}EXPORT_SYMBOL(netpoll_poll_dev);
void netpoll_poll_disable(struct net_device *dev){ struct netpoll_info *ni;
might_sleep(); ni = rtnl_dereference(dev->npinfo); if (ni) down(&ni->dev_lock);}
void netpoll_poll_enable(struct net_device *dev){ struct netpoll_info *ni;
ni = rtnl_dereference(dev->npinfo); if (ni) up(&ni->dev_lock);}
void netpoll_zap_completion_queue(void){ unsigned long flags; struct softnet_data *sd = &get_cpu_var(softnet_data);
if (sd->completion_queue) { struct sk_buff *clist;
local_irq_save(flags); clist = sd->completion_queue; sd->completion_queue = NULL; local_irq_restore(flags);
while (clist != NULL) { struct sk_buff *skb = clist; clist = clist->next; if (!skb_irq_freeable(skb)) { refcount_set(&skb->users, 1); dev_kfree_skb_any(skb); /* put this one back */ } else { __kfree_skb(skb); } } }
put_cpu_var(softnet_data);}EXPORT_SYMBOL_NS_GPL(netpoll_zap_completion_queue, "NETDEV_INTERNAL");
static int netpoll_owner_active(struct net_device *dev){ struct napi_struct *napi;
list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) { if (READ_ONCE(napi->poll_owner) == smp_processor_id()) return 1; } return 0;}
/* call with IRQ disabled */static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb){ netdev_tx_t status = NETDEV_TX_BUSY; netdev_tx_t ret = NET_XMIT_DROP; struct net_device *dev; unsigned long tries; /* It is up to the caller to keep npinfo alive. */ struct netpoll_info *npinfo;
lockdep_assert_irqs_disabled();
dev = np->dev; /* npinfo->txq belongs to np->dev, so retries must stay bound to it. */ skb->dev = dev; rcu_read_lock(); npinfo = rcu_dereference_bh(dev->npinfo);
if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) { dev_kfree_skb_irq(skb); goto out; }
/* don't get messages out of order, and no recursion */ if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) { struct netdev_queue *txq;
txq = netdev_core_pick_tx(dev, skb, NULL);
/* try until next clock tick */ for (tries = jiffies_to_usecs(1)/USEC_PER_POLL; tries > 0; --tries) { if (HARD_TX_TRYLOCK(dev, txq)) { if (!netif_xmit_stopped(txq)) status = netpoll_start_xmit(skb, dev, txq);
HARD_TX_UNLOCK(dev, txq);
if (dev_xmit_complete(status)) break;
}
/* tickle device maybe there is some cleanup */ netpoll_poll_dev(np->dev);
udelay(USEC_PER_POLL); }
WARN_ONCE(!irqs_disabled(), "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pS)\n", dev->name, dev->netdev_ops->ndo_start_xmit);
}
if (!dev_xmit_complete(status)) { if (skb_queue_len_lockless(&npinfo->txq) >= NETPOLL_TXQ_MAX) { dev_core_stats_tx_dropped_inc(dev); dev_kfree_skb_irq_reason(skb, SKB_DROP_REASON_FULL_RING); goto out; } skb_queue_tail(&npinfo->txq, skb); schedule_delayed_work(&npinfo->tx_work,0); } ret = NETDEV_TX_OK;out: rcu_read_unlock(); return ret;}
netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb){ unsigned long flags; netdev_tx_t ret;
if (unlikely(!np)) { dev_kfree_skb_irq(skb); ret = NET_XMIT_DROP; } else { local_irq_save(flags); ret = __netpoll_send_skb(np, skb); local_irq_restore(flags); } return ret;}EXPORT_SYMBOL(netpoll_send_skb);
int __netpoll_setup(struct netpoll *np, struct net_device *ndev){ struct netpoll_info *npinfo; const struct net_device_ops *ops; int err;
if (ndev->priv_flags & IFF_DISABLE_NETPOLL) { np_err(np, "%s doesn't support polling, aborting\n", ndev->name); err = -ENOTSUPP; goto out; }
npinfo = rtnl_dereference(ndev->npinfo); if (!npinfo) { npinfo = kmalloc_obj(*npinfo); if (!npinfo) { err = -ENOMEM; goto out; }
sema_init(&npinfo->dev_lock, 1); skb_queue_head_init(&npinfo->txq); INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
refcount_set(&npinfo->refcnt, 1);
ops = ndev->netdev_ops; if (ops->ndo_netpoll_setup) { err = ops->ndo_netpoll_setup(ndev); if (err) goto free_npinfo; } } else { refcount_inc(&npinfo->refcnt); }
np->dev = ndev; strscpy(np->dev_name, ndev->name, IFNAMSIZ);
/* last thing to do is link it to the net device structure */ rcu_assign_pointer(ndev->npinfo, npinfo);
return 0;
free_npinfo: kfree(npinfo);out: return err;}EXPORT_SYMBOL_GPL(__netpoll_setup);
static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head){ struct netpoll_info *npinfo = container_of(rcu_head, struct netpoll_info, rcu);
skb_queue_purge(&npinfo->txq); kfree(npinfo);}
static void __netpoll_cleanup(struct netpoll *np){ struct netpoll_info *npinfo;
npinfo = rtnl_dereference(np->dev->npinfo); if (!npinfo) return;
/* At this point, there is a single npinfo instance per netdevice, and * its refcnt tracks how many netpoll structures are linked to it. We * only perform npinfo cleanup when the refcnt decrements to zero. */ if (refcount_dec_and_test(&npinfo->refcnt)) { const struct net_device_ops *ops;
ops = np->dev->netdev_ops; if (ops->ndo_netpoll_cleanup) ops->ndo_netpoll_cleanup(np->dev);
RCU_INIT_POINTER(np->dev->npinfo, NULL); disable_delayed_work_sync(&npinfo->tx_work); call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info); }}
void __netpoll_free(struct netpoll *np){ ASSERT_RTNL();
/* Wait for transmitting packets to finish before freeing. */ synchronize_net(); __netpoll_cleanup(np); kfree(np);}EXPORT_SYMBOL_GPL(__netpoll_free);
void do_netpoll_cleanup(struct netpoll *np){ __netpoll_cleanup(np); netdev_put(np->dev, &np->dev_tracker); np->dev = NULL;}EXPORT_SYMBOL(do_netpoll_cleanup);
void netpoll_cleanup(struct netpoll *np){ rtnl_lock(); if (!np->dev) goto out; do_netpoll_cleanup(np);out: rtnl_unlock();}EXPORT_SYMBOL(netpoll_cleanup);