1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_NET_QUEUES_H 3 #define _LINUX_NET_QUEUES_H 4 5 #include <linux/netdevice.h> 6 7 /* See the netdev.yaml spec for definition of each statistic */ 8 struct netdev_queue_stats_rx { 9 u64 bytes; 10 u64 packets; 11 u64 alloc_fail; 12 13 u64 hw_drops; 14 u64 hw_drop_overruns; 15 16 u64 csum_unnecessary; 17 u64 csum_none; 18 u64 csum_bad; 19 20 u64 hw_gro_packets; 21 u64 hw_gro_bytes; 22 u64 hw_gro_wire_packets; 23 u64 hw_gro_wire_bytes; 24 25 u64 hw_drop_ratelimits; 26 }; 27 28 struct netdev_queue_stats_tx { 29 u64 bytes; 30 u64 packets; 31 32 u64 hw_drops; 33 u64 hw_drop_errors; 34 35 u64 csum_none; 36 u64 needs_csum; 37 38 u64 hw_gso_packets; 39 u64 hw_gso_bytes; 40 u64 hw_gso_wire_packets; 41 u64 hw_gso_wire_bytes; 42 43 u64 hw_drop_ratelimits; 44 45 u64 stop; 46 u64 wake; 47 }; 48 49 /** 50 * struct netdev_stat_ops - netdev ops for fine grained stats 51 * @get_queue_stats_rx: get stats for a given Rx queue 52 * @get_queue_stats_tx: get stats for a given Tx queue 53 * @get_base_stats: get base stats (not belonging to any live instance) 54 * 55 * Query stats for a given object. The values of the statistics are undefined 56 * on entry (specifically they are *not* zero-initialized). Drivers should 57 * assign values only to the statistics they collect. Statistics which are not 58 * collected must be left undefined. 59 * 60 * Queue objects are not necessarily persistent, and only currently active 61 * queues are queried by the per-queue callbacks. This means that per-queue 62 * statistics will not generally add up to the total number of events for 63 * the device. The @get_base_stats callback allows filling in the delta 64 * between events for currently live queues and overall device history. 65 * When the statistics for the entire device are queried, first @get_base_stats 66 * is issued to collect the delta, and then a series of per-queue callbacks. 67 * Only statistics which are set in @get_base_stats will be reported 68 * at the device level, meaning that unlike in queue callbacks, setting 69 * a statistic to zero in @get_base_stats is a legitimate thing to do. 70 * This is because @get_base_stats has a second function of designating which 71 * statistics are in fact correct for the entire device (e.g. when history 72 * for some of the events is not maintained, and reliable "total" cannot 73 * be provided). 74 * 75 * Device drivers can assume that when collecting total device stats, 76 * the @get_base_stats and subsequent per-queue calls are performed 77 * "atomically" (without releasing the rtnl_lock). 78 * 79 * Device drivers are encouraged to reset the per-queue statistics when 80 * number of queues change. This is because the primary use case for 81 * per-queue statistics is currently to detect traffic imbalance. 82 */ 83 struct netdev_stat_ops { 84 void (*get_queue_stats_rx)(struct net_device *dev, int idx, 85 struct netdev_queue_stats_rx *stats); 86 void (*get_queue_stats_tx)(struct net_device *dev, int idx, 87 struct netdev_queue_stats_tx *stats); 88 void (*get_base_stats)(struct net_device *dev, 89 struct netdev_queue_stats_rx *rx, 90 struct netdev_queue_stats_tx *tx); 91 }; 92 93 /** 94 * struct netdev_queue_mgmt_ops - netdev ops for queue management 95 * 96 * @ndo_queue_mem_size: Size of the struct that describes a queue's memory. 97 * 98 * @ndo_queue_mem_alloc: Allocate memory for an RX queue at the specified index. 99 * The new memory is written at the specified address. 100 * 101 * @ndo_queue_mem_free: Free memory from an RX queue. 102 * 103 * @ndo_queue_start: Start an RX queue with the specified memory and at the 104 * specified index. 105 * 106 * @ndo_queue_stop: Stop the RX queue at the specified index. The stopped 107 * queue's memory is written at the specified address. 108 */ 109 struct netdev_queue_mgmt_ops { 110 size_t ndo_queue_mem_size; 111 int (*ndo_queue_mem_alloc)(struct net_device *dev, 112 void *per_queue_mem, 113 int idx); 114 void (*ndo_queue_mem_free)(struct net_device *dev, 115 void *per_queue_mem); 116 int (*ndo_queue_start)(struct net_device *dev, 117 void *per_queue_mem, 118 int idx); 119 int (*ndo_queue_stop)(struct net_device *dev, 120 void *per_queue_mem, 121 int idx); 122 }; 123 124 /** 125 * DOC: Lockless queue stopping / waking helpers. 126 * 127 * The netif_txq_maybe_stop() and __netif_txq_completed_wake() 128 * macros are designed to safely implement stopping 129 * and waking netdev queues without full lock protection. 130 * 131 * We assume that there can be no concurrent stop attempts and no concurrent 132 * wake attempts. The try-stop should happen from the xmit handler, 133 * while wake up should be triggered from NAPI poll context. 134 * The two may run concurrently (single producer, single consumer). 135 * 136 * The try-stop side is expected to run from the xmit handler and therefore 137 * it does not reschedule Tx (netif_tx_start_queue() instead of 138 * netif_tx_wake_queue()). Uses of the ``stop`` macros outside of the xmit 139 * handler may lead to xmit queue being enabled but not run. 140 * The waking side does not have similar context restrictions. 141 * 142 * The macros guarantee that rings will not remain stopped if there's 143 * space available, but they do *not* prevent false wake ups when 144 * the ring is full! Drivers should check for ring full at the start 145 * for the xmit handler. 146 * 147 * All descriptor ring indexes (and other relevant shared state) must 148 * be updated before invoking the macros. 149 */ 150 151 #define netif_txq_try_stop(txq, get_desc, start_thrs) \ 152 ({ \ 153 int _res; \ 154 \ 155 netif_tx_stop_queue(txq); \ 156 /* Producer index and stop bit must be visible \ 157 * to consumer before we recheck. \ 158 * Pairs with a barrier in __netif_txq_completed_wake(). \ 159 */ \ 160 smp_mb__after_atomic(); \ 161 \ 162 /* We need to check again in a case another \ 163 * CPU has just made room available. \ 164 */ \ 165 _res = 0; \ 166 if (unlikely(get_desc >= start_thrs)) { \ 167 netif_tx_start_queue(txq); \ 168 _res = -1; \ 169 } \ 170 _res; \ 171 }) \ 172 173 /** 174 * netif_txq_maybe_stop() - locklessly stop a Tx queue, if needed 175 * @txq: struct netdev_queue to stop/start 176 * @get_desc: get current number of free descriptors (see requirements below!) 177 * @stop_thrs: minimal number of available descriptors for queue to be left 178 * enabled 179 * @start_thrs: minimal number of descriptors to re-enable the queue, can be 180 * equal to @stop_thrs or higher to avoid frequent waking 181 * 182 * All arguments may be evaluated multiple times, beware of side effects. 183 * @get_desc must be a formula or a function call, it must always 184 * return up-to-date information when evaluated! 185 * Expected to be used from ndo_start_xmit, see the comment on top of the file. 186 * 187 * Returns: 188 * 0 if the queue was stopped 189 * 1 if the queue was left enabled 190 * -1 if the queue was re-enabled (raced with waking) 191 */ 192 #define netif_txq_maybe_stop(txq, get_desc, stop_thrs, start_thrs) \ 193 ({ \ 194 int _res; \ 195 \ 196 _res = 1; \ 197 if (unlikely(get_desc < stop_thrs)) \ 198 _res = netif_txq_try_stop(txq, get_desc, start_thrs); \ 199 _res; \ 200 }) \ 201 202 /* Variant of netdev_tx_completed_queue() which guarantees smp_mb() if 203 * @bytes != 0, regardless of kernel config. 204 */ 205 static inline void 206 netdev_txq_completed_mb(struct netdev_queue *dev_queue, 207 unsigned int pkts, unsigned int bytes) 208 { 209 if (IS_ENABLED(CONFIG_BQL)) 210 netdev_tx_completed_queue(dev_queue, pkts, bytes); 211 else if (bytes) 212 smp_mb(); 213 } 214 215 /** 216 * __netif_txq_completed_wake() - locklessly wake a Tx queue, if needed 217 * @txq: struct netdev_queue to stop/start 218 * @pkts: number of packets completed 219 * @bytes: number of bytes completed 220 * @get_desc: get current number of free descriptors (see requirements below!) 221 * @start_thrs: minimal number of descriptors to re-enable the queue 222 * @down_cond: down condition, predicate indicating that the queue should 223 * not be woken up even if descriptors are available 224 * 225 * All arguments may be evaluated multiple times. 226 * @get_desc must be a formula or a function call, it must always 227 * return up-to-date information when evaluated! 228 * Reports completed pkts/bytes to BQL. 229 * 230 * Returns: 231 * 0 if the queue was woken up 232 * 1 if the queue was already enabled (or disabled but @down_cond is true) 233 * -1 if the queue was left unchanged (@start_thrs not reached) 234 */ 235 #define __netif_txq_completed_wake(txq, pkts, bytes, \ 236 get_desc, start_thrs, down_cond) \ 237 ({ \ 238 int _res; \ 239 \ 240 /* Report to BQL and piggy back on its barrier. \ 241 * Barrier makes sure that anybody stopping the queue \ 242 * after this point sees the new consumer index. \ 243 * Pairs with barrier in netif_txq_try_stop(). \ 244 */ \ 245 netdev_txq_completed_mb(txq, pkts, bytes); \ 246 \ 247 _res = -1; \ 248 if (pkts && likely(get_desc >= start_thrs)) { \ 249 _res = 1; \ 250 if (unlikely(netif_tx_queue_stopped(txq)) && \ 251 !(down_cond)) { \ 252 netif_tx_wake_queue(txq); \ 253 _res = 0; \ 254 } \ 255 } \ 256 _res; \ 257 }) 258 259 #define netif_txq_completed_wake(txq, pkts, bytes, get_desc, start_thrs) \ 260 __netif_txq_completed_wake(txq, pkts, bytes, get_desc, start_thrs, false) 261 262 /* subqueue variants follow */ 263 264 #define netif_subqueue_try_stop(dev, idx, get_desc, start_thrs) \ 265 ({ \ 266 struct netdev_queue *txq; \ 267 \ 268 txq = netdev_get_tx_queue(dev, idx); \ 269 netif_txq_try_stop(txq, get_desc, start_thrs); \ 270 }) 271 272 #define netif_subqueue_maybe_stop(dev, idx, get_desc, stop_thrs, start_thrs) \ 273 ({ \ 274 struct netdev_queue *txq; \ 275 \ 276 txq = netdev_get_tx_queue(dev, idx); \ 277 netif_txq_maybe_stop(txq, get_desc, stop_thrs, start_thrs); \ 278 }) 279 280 #define netif_subqueue_completed_wake(dev, idx, pkts, bytes, \ 281 get_desc, start_thrs) \ 282 ({ \ 283 struct netdev_queue *txq; \ 284 \ 285 txq = netdev_get_tx_queue(dev, idx); \ 286 netif_txq_completed_wake(txq, pkts, bytes, \ 287 get_desc, start_thrs); \ 288 }) 289 290 #endif 291