/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_NET_QUEUES_H #define _LINUX_NET_QUEUES_H #include <linux/netdevice.h> /** * struct netdev_config - queue-related configuration for a netdev * @hds_thresh: HDS Threshold value. * @hds_config: HDS value from userspace. */ struct netdev_config { u32 hds_thresh; u8 hds_config; }; struct netdev_queue_config { u32 rx_page_size; }; /* See the netdev.yaml spec for definition of each statistic */ struct netdev_queue_stats_rx { u64 bytes; u64 packets; u64 alloc_fail; u64 hw_drops; u64 hw_drop_overruns; u64 csum_complete; u64 csum_unnecessary; u64 csum_none; u64 csum_bad; u64 hw_gro_packets; u64 hw_gro_bytes; u64 hw_gro_wire_packets; u64 hw_gro_wire_bytes; u64 hw_drop_ratelimits; }; struct netdev_queue_stats_tx { u64 bytes; u64 packets; u64 hw_drops; u64 hw_drop_errors; u64 csum_none; u64 needs_csum; u64 hw_gso_packets; u64 hw_gso_bytes; u64 hw_gso_wire_packets; u64 hw_gso_wire_bytes; u64 hw_drop_ratelimits; u64 stop; u64 wake; }; /** * struct netdev_stat_ops - netdev ops for fine grained stats * @get_queue_stats_rx: get stats for a given Rx queue * @get_queue_stats_tx: get stats for a given Tx queue * @get_base_stats: get base stats (not belonging to any live instance) * * Query stats for a given object. The values of the statistics are undefined * on entry (specifically they are *not* zero-initialized). Drivers should * assign values only to the statistics they collect. Statistics which are not * collected must be left undefined. * * Queue objects are not necessarily persistent, and only currently active * queues are queried by the per-queue callbacks. This means that per-queue * statistics will not generally add up to the total number of events for * the device. The @get_base_stats callback allows filling in the delta * between events for currently live queues and overall device history. * @get_base_stats can also be used to report any miscellaneous packets * transferred outside of the main set of queues used by the networking stack. * When the statistics for the entire device are queried, first @get_base_stats * is issued to collect the delta, and then a series of per-queue callbacks. * Only statistics which are set in @get_base_stats will be reported * at the device level, meaning that unlike in queue callbacks, setting * a statistic to zero in @get_base_stats is a legitimate thing to do. * This is because @get_base_stats has a second function of designating which * statistics are in fact correct for the entire device (e.g. when history * for some of the events is not maintained, and reliable "total" cannot * be provided). * * Ops are called under the instance lock if netdev_need_ops_lock() * returns true, otherwise under rtnl_lock. * Device drivers can assume that when collecting total device stats, * the @get_base_stats and subsequent per-queue calls are performed * "atomically" (without releasing the relevant lock). * * Device drivers are encouraged to reset the per-queue statistics when * number of queues change. This is because the primary use case for * per-queue statistics is currently to detect traffic imbalance. */ struct netdev_stat_ops { void (*get_queue_stats_rx)(struct net_device *dev, int idx, struct netdev_queue_stats_rx *stats); void (*get_queue_stats_tx)(struct net_device *dev, int idx, struct netdev_queue_stats_tx *stats); void (*get_base_stats)(struct net_device *dev, struct netdev_queue_stats_rx *rx, struct netdev_queue_stats_tx *tx); }; void netdev_stat_queue_sum(struct net_device *netdev, int rx_start, int rx_end, struct netdev_queue_stats_rx *rx_sum, int tx_start, int tx_end, struct netdev_queue_stats_tx *tx_sum); enum { /* The queue checks and honours the page size qcfg parameter */ QCFG_RX_PAGE_SIZE = 0x1, }; /** * struct netdev_queue_mgmt_ops - netdev ops for queue management * * @ndo_queue_mem_size: Size of the struct that describes a queue's memory. * * @ndo_queue_mem_alloc: Allocate memory for an RX queue at the specified index. * The new memory is written at the specified address. * * @ndo_queue_mem_free: Free memory from an RX queue. * * @ndo_queue_start: Start an RX queue with the specified memory and at the * specified index. * * @ndo_queue_stop: Stop the RX queue at the specified index. The stopped * queue's memory is written at the specified address. * * @ndo_queue_get_dma_dev: Get dma device for zero-copy operations to be used * for this queue. Return NULL on error. * * @ndo_default_qcfg: (Optional) Populate queue config struct with defaults. * Queue config structs are passed to this helper before * the user-requested settings are applied. * * @ndo_validate_qcfg: (Optional) Check if queue config is supported. * Called when configuration affecting a queue may be * changing, either due to NIC-wide config, or config * scoped to the queue at a specified index. * When NIC-wide config is changed the callback will * be invoked for all queues. * * @supported_params: Bitmask of supported parameters, see QCFG_*. * * Note that @ndo_queue_mem_alloc and @ndo_queue_mem_free may be called while * the interface is closed. @ndo_queue_start and @ndo_queue_stop will only * be called for an interface which is open. */ struct netdev_queue_mgmt_ops { size_t ndo_queue_mem_size; int (*ndo_queue_mem_alloc)(struct net_device *dev, struct netdev_queue_config *qcfg, void *per_queue_mem, int idx); void (*ndo_queue_mem_free)(struct net_device *dev, void *per_queue_mem); int (*ndo_queue_start)(struct net_device *dev, struct netdev_queue_config *qcfg, void *per_queue_mem, int idx); int (*ndo_queue_stop)(struct net_device *dev, void *per_queue_mem, int idx); void (*ndo_default_qcfg)(struct net_device *dev, struct netdev_queue_config *qcfg); int (*ndo_validate_qcfg)(struct net_device *dev, struct netdev_queue_config *qcfg, struct netlink_ext_ack *extack); struct device * (*ndo_queue_get_dma_dev)(struct net_device *dev, int idx); unsigned int supported_params; }; void netdev_queue_config(struct net_device *dev, int rxq, struct netdev_queue_config *qcfg); bool netif_rxq_has_unreadable_mp(struct net_device *dev, int idx); /** * DOC: Lockless queue stopping / waking helpers. * * The netif_txq_maybe_stop() and __netif_txq_completed_wake() * macros are designed to safely implement stopping * and waking netdev queues without full lock protection. * * We assume that there can be no concurrent stop attempts and no concurrent * wake attempts. The try-stop should happen from the xmit handler, * while wake up should be triggered from NAPI poll context. * The two may run concurrently (single producer, single consumer). * * The try-stop side is expected to run from the xmit handler and therefore * it does not reschedule Tx (netif_tx_start_queue() instead of * netif_tx_wake_queue()). Uses of the ``stop`` macros outside of the xmit * handler may lead to xmit queue being enabled but not run. * The waking side does not have similar context restrictions. * * The macros guarantee that rings will not remain stopped if there's * space available, but they do *not* prevent false wake ups when * the ring is full! Drivers should check for ring full at the start * for the xmit handler. * * All descriptor ring indexes (and other relevant shared state) must * be updated before invoking the macros. */ #define netif_txq_try_stop(txq, get_desc, start_thrs) \ ({ \ int _res; \ \ netif_tx_stop_queue(txq); \ /* Producer index and stop bit must be visible \ * to consumer before we recheck. \ * Pairs with a barrier in __netif_txq_completed_wake(). \ */ \ smp_mb__after_atomic(); \ \ /* We need to check again in a case another \ * CPU has just made room available. \ */ \ _res = 0; \ if (unlikely(get_desc >= start_thrs)) { \ netif_tx_start_queue(txq); \ _res = -1; \ } \ _res; \ }) \ /** * netif_txq_maybe_stop() - locklessly stop a Tx queue, if needed * @txq: struct netdev_queue to stop/start * @get_desc: get current number of free descriptors (see requirements below!) * @stop_thrs: minimal number of available descriptors for queue to be left * enabled * @start_thrs: minimal number of descriptors to re-enable the queue, can be * equal to @stop_thrs or higher to avoid frequent waking * * All arguments may be evaluated multiple times, beware of side effects. * @get_desc must be a formula or a function call, it must always * return up-to-date information when evaluated! * Expected to be used from ndo_start_xmit, see the comment on top of the file. * * Returns: * 0 if the queue was stopped * 1 if the queue was left enabled * -1 if the queue was re-enabled (raced with waking) */ #define netif_txq_maybe_stop(txq, get_desc, stop_thrs, start_thrs) \ ({ \ int _res; \ \ _res = 1; \ if (unlikely(get_desc < stop_thrs)) \ _res = netif_txq_try_stop(txq, get_desc, start_thrs); \ _res; \ }) \ /* Variant of netdev_tx_completed_queue() which guarantees smp_mb() if * @bytes != 0, regardless of kernel config. */ static inline void netdev_txq_completed_mb(struct netdev_queue *dev_queue, unsigned int pkts, unsigned int bytes) { if (IS_ENABLED(CONFIG_BQL)) netdev_tx_completed_queue(dev_queue, pkts, bytes); else if (bytes) smp_mb(); } /** * __netif_txq_completed_wake() - locklessly wake a Tx queue, if needed * @txq: struct netdev_queue to stop/start * @pkts: number of packets completed * @bytes: number of bytes completed * @get_desc: get current number of free descriptors (see requirements below!) * @start_thrs: minimal number of descriptors to re-enable the queue * @down_cond: down condition, predicate indicating that the queue should * not be woken up even if descriptors are available * * All arguments may be evaluated multiple times. * @get_desc must be a formula or a function call, it must always * return up-to-date information when evaluated! * Reports completed pkts/bytes to BQL. * * Returns: * 0 if the queue was woken up * 1 if the queue was already enabled (or disabled but @down_cond is true) * -1 if the queue was left unchanged (@start_thrs not reached) */ #define __netif_txq_completed_wake(txq, pkts, bytes, \ get_desc, start_thrs, down_cond) \ ({ \ int _res; \ \ /* Report to BQL and piggy back on its barrier. \ * Barrier makes sure that anybody stopping the queue \ * after this point sees the new consumer index. \ * Pairs with barrier in netif_txq_try_stop(). \ */ \ netdev_txq_completed_mb(txq, pkts, bytes); \ \ _res = -1; \ if (pkts && likely(get_desc >= start_thrs)) { \ _res = 1; \ if (unlikely(netif_tx_queue_stopped(txq)) && \ !(down_cond)) { \ netif_tx_wake_queue(txq); \ _res = 0; \ } \ } \ _res; \ }) #define netif_txq_completed_wake(txq, pkts, bytes, get_desc, start_thrs) \ __netif_txq_completed_wake(txq, pkts, bytes, get_desc, start_thrs, false) /* subqueue variants follow */ #define netif_subqueue_try_stop(dev, idx, get_desc, start_thrs) \ ({ \ struct netdev_queue *_txq; \ \ _txq = netdev_get_tx_queue(dev, idx); \ netif_txq_try_stop(_txq, get_desc, start_thrs); \ }) static inline void netif_subqueue_sent(const struct net_device *dev, unsigned int idx, unsigned int bytes) { struct netdev_queue *txq; txq = netdev_get_tx_queue(dev, idx); netdev_tx_sent_queue(txq, bytes); } static inline unsigned int netif_xmit_timeout_ms(struct netdev_queue *txq) { unsigned long trans_start = READ_ONCE(txq->trans_start); if (netif_xmit_stopped(txq) && time_after(jiffies, trans_start + txq->dev->watchdog_timeo)) return jiffies_to_msecs(jiffies - trans_start); return 0; } #define netif_subqueue_maybe_stop(dev, idx, get_desc, stop_thrs, start_thrs) \ ({ \ struct netdev_queue *_txq; \ \ _txq = netdev_get_tx_queue(dev, idx); \ netif_txq_maybe_stop(_txq, get_desc, stop_thrs, start_thrs); \ }) #define netif_subqueue_completed_wake(dev, idx, pkts, bytes, \ get_desc, start_thrs) \ ({ \ struct netdev_queue *_txq; \ \ _txq = netdev_get_tx_queue(dev, idx); \ netif_txq_completed_wake(_txq, pkts, bytes, \ get_desc, start_thrs); \ }) struct device *netdev_queue_get_dma_dev(struct net_device *dev, int idx); #endif
