net: remove NETDEV_TX_LOCKED support
No more users in the tree, remove NETDEV_TX_LOCKED support. Adds another hole in softnet_stats struct, but better than keeping the unused collision counter around. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Westphal
David S. Miller
parent
a6086a8937
commit
f0cdf76c10
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@ -131,13 +131,11 @@ stack. Driver should not change behaviour based on them.
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* LLTX driver (deprecated for hardware drivers)
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NETIF_F_LLTX should be set in drivers that implement their own locking in
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transmit path or don't need locking at all (e.g. software tunnels).
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In ndo_start_xmit, it is recommended to use a try_lock and return
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NETDEV_TX_LOCKED when the spin lock fails. The locking should also properly
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protect against other callbacks (the rules you need to find out).
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NETIF_F_LLTX is meant to be used by drivers that don't need locking at all,
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e.g. software tunnels.
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Don't use it for new drivers.
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This is also used in a few legacy drivers that implement their
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own locking, don't use it for new (hardware) drivers.
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* netns-local device
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@ -69,10 +69,9 @@ ndo_start_xmit:
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When the driver sets NETIF_F_LLTX in dev->features this will be
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called without holding netif_tx_lock. In this case the driver
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has to lock by itself when needed. It is recommended to use a try lock
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for this and return NETDEV_TX_LOCKED when the spin lock fails.
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The locking there should also properly protect against
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set_rx_mode. Note that the use of NETIF_F_LLTX is deprecated.
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has to lock by itself when needed.
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The locking there should also properly protect against
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set_rx_mode. WARNING: use of NETIF_F_LLTX is deprecated.
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Don't use it for new drivers.
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Context: Process with BHs disabled or BH (timer),
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@ -83,8 +82,6 @@ ndo_start_xmit:
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o NETDEV_TX_BUSY Cannot transmit packet, try later
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Usually a bug, means queue start/stop flow control is broken in
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the driver. Note: the driver must NOT put the skb in its DMA ring.
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o NETDEV_TX_LOCKED Locking failed, please retry quickly.
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Only valid when NETIF_F_LLTX is set.
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ndo_tx_timeout:
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Synchronization: netif_tx_lock spinlock; all TX queues frozen.
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@ -106,7 +106,6 @@ enum netdev_tx {
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__NETDEV_TX_MIN = INT_MIN, /* make sure enum is signed */
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NETDEV_TX_OK = 0x00, /* driver took care of packet */
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NETDEV_TX_BUSY = 0x10, /* driver tx path was busy*/
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NETDEV_TX_LOCKED = 0x20, /* driver tx lock was already taken */
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};
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typedef enum netdev_tx netdev_tx_t;
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@ -831,7 +830,6 @@ struct tc_to_netdev {
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* the queue before that can happen; it's for obsolete devices and weird
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* corner cases, but the stack really does a non-trivial amount
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* of useless work if you return NETDEV_TX_BUSY.
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* (can also return NETDEV_TX_LOCKED iff NETIF_F_LLTX)
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* Required; cannot be NULL.
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*
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* netdev_features_t (*ndo_fix_features)(struct net_device *dev,
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@ -2737,7 +2735,6 @@ struct softnet_data {
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/* stats */
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unsigned int processed;
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unsigned int time_squeeze;
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unsigned int cpu_collision;
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unsigned int received_rps;
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#ifdef CONFIG_RPS
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struct softnet_data *rps_ipi_list;
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@ -162,7 +162,8 @@ static int softnet_seq_show(struct seq_file *seq, void *v)
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"%08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x\n",
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sd->processed, sd->dropped, sd->time_squeeze, 0,
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0, 0, 0, 0, /* was fastroute */
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sd->cpu_collision, sd->received_rps, flow_limit_count);
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0, /* was cpu_collision */
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sd->received_rps, flow_limit_count);
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return 0;
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}
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@ -3472,7 +3472,6 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
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pkt_dev->odevname, ret);
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pkt_dev->errors++;
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/* fallthru */
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case NETDEV_TX_LOCKED:
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case NETDEV_TX_BUSY:
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/* Retry it next time */
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atomic_dec(&(pkt_dev->skb->users));
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@ -108,35 +108,6 @@ static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
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return skb;
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}
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static inline int handle_dev_cpu_collision(struct sk_buff *skb,
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struct netdev_queue *dev_queue,
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struct Qdisc *q)
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{
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int ret;
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if (unlikely(dev_queue->xmit_lock_owner == smp_processor_id())) {
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/*
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* Same CPU holding the lock. It may be a transient
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* configuration error, when hard_start_xmit() recurses. We
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* detect it by checking xmit owner and drop the packet when
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* deadloop is detected. Return OK to try the next skb.
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*/
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kfree_skb_list(skb);
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net_warn_ratelimited("Dead loop on netdevice %s, fix it urgently!\n",
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dev_queue->dev->name);
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ret = qdisc_qlen(q);
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} else {
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/*
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* Another cpu is holding lock, requeue & delay xmits for
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* some time.
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*/
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__this_cpu_inc(softnet_data.cpu_collision);
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ret = dev_requeue_skb(skb, q);
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}
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return ret;
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}
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/*
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* Transmit possibly several skbs, and handle the return status as
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* required. Holding the __QDISC___STATE_RUNNING bit guarantees that
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@ -174,9 +145,6 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
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if (dev_xmit_complete(ret)) {
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/* Driver sent out skb successfully or skb was consumed */
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ret = qdisc_qlen(q);
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} else if (ret == NETDEV_TX_LOCKED) {
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/* Driver try lock failed */
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ret = handle_dev_cpu_collision(skb, txq, q);
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} else {
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/* Driver returned NETDEV_TX_BUSY - requeue skb */
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if (unlikely(ret != NETDEV_TX_BUSY))
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